Author: ecogrow

Consequently, lower NO3 – concentration and lower NO3 – :Clratio are predicted in the silty loam vadose zone as compared to the sandy loam column. It is interesting to note that while greater NO3 – loss and denitrification are predicted for the silty loam vadose zone, carbon concentration associated with the shallow vadose zone are comparatively lower than for the sandy loam column. Moreover, the calculated pH is lower and iron concentrations are higher in the silt loam profile below the top meter when compared to the same depths within the sandy loam column . This suggests that chemolithoautotrophic reactions could be more important for these finer textured sediments. While both heterotrophic and chemolithoautotrophic reactions would be expected to result in a pH decrease , the greater decline in pH and concomitant increase in Fe+3 concentration suggests the importance of Fe and S redox cycling associated with the chemolithoautotrophic reactions in silty loam sediments . Evolving from these steady state conditions, scenario S1 suggests that denitrification is enhanced as floodwater infiltrates into the silt loam column. Model results indicate that saturation increases to 80% from 1 to 4 m depths and O2 decreases from 2.1 x 10-4 mol L-1 to 1.7 x 10-4 mol L -1 , resulting in 43% of the NO3 – being denitrified for this scenario . In comparison to the homogeneous profiles, the sandy loam with silt loam channel stratigraphy has higher calculated water contents and slightly lower O2 concentration within and surrounding the silt loam channel than the homogenous sandy loam column under steady state conditions . Calculated NO3 – concentrations are also similar between the homogenous sandy loam column and SaSi case,flower display buckets except for within and below the silt loam channel where lower NO3 – concentration was predicted .

For scenario S1, water content for the SaSi case increased in a manner similar to the homogenous sandy loam, except for within the silt loam channel, which increased from 60 to 81%. Figure 4 further demonstrates that the infiltrating floodwater resulted in an increase in NO3 – concentration between 1 and 3 m within the sandy loam textured soil, but a decrease elsewhere. Within the channel itself , lower nitrate and NO3 – :Clratio are predicted, suggesting higher rates of denitrification . Overall, the model results indicate that an average of 37% of the NO3 – concentration is denitrified in the SaSi case 60 days after flooding, with 35% denitrification occurring in the sandy loam matrix and 40% occurring within the silt loam channel. Furthermore, the silt loam channel has lower carbon and higher Fe+3 concentrations similar to the homogenous silt loam column again suggesting the importance of both heterotrophic and chemolithoautotrophic denitrification in these finer textured sediments. In comparison to the SaSi case, calculated water saturation and O2 profiles were markedly different between the homogenous silt loam column and the silt loam with sandy loam channel under steady state conditions . In particular, the sandy loam channel has lower calculated water content than the homogenous silt loam column . Further, greater gas flux within the channel resulted in 11-19% higher O2 concentration that penetrated deeper into the vadose zone as compared to the homogeneously textured column. NO3 – concentration are also estimated to penetrate deeper into the vadose zone in the SiSa case due to the high permeability of the sandy loam channel .

While carbon concentration also penetrated deeper in the vadose zone in the SiSa case, higher calculated O2 concentration did not allow for comparable rates of denitrification below 1 m in this case as observed in the homogenous silt loam profile. This is further confirmed by the lower NO3 – :Clratio, which indicates that transport processes dominate biogeochemical fluxes within this column . With scenario S1, the calculated water content increased to 48% saturation while the O2 concentration remained the same within the channel. The high permeability channel allowed for NO3 – to move faster and deeper into the vadose zone. Overall, calculated denitrification was lower in the SiSa case as compared to the homogeneous textured column. In the simplified ERT stratigraphy, similar patterns were observed such that high permeability channels transported water, O2, and NO3 – faster and deeper into the subsurface than low permeability regions . As a result, concentration profiles showed significant variability across the modeled domain even under steady state conditions. For example, the calculated O2 and NO3 – concentrations are an order of magnitude lower in the shallow vadose zone below the limiting layer than within the preferential flow channel. Higher NO3 – :Clratio within the channel further confirms that preferential flow paths transport higher quantities of dissolved aqueous species without their being impacted by other processes such as denitrification . Other interesting trends are shown by carbon and Fe+2 concentrations within the modeled column. Dissolved carbon in particular is predicted to have a lower concentration in the preferential flow channel and the matrix surrounding the channel than below the limiting layer. In contrast, the Fe+2 concentration is estimated to be higher in the matrix surrounding the preferential flow channel and below the limiting layer . For scenario S1, model results indicate that NO3 – moved through the preferential flow path faster and deeper into the profile, while the limiting layer acts as a denitrification barrier as evidenced by the decrease in NO3 – :Clratio.

The highest denitrification was estimated to occur in the matrix adjacent to the preferential flow channel , followed by intermediate nitrate reduction below the limiting layer and far away from the channel , while the lowest denitrification was estimated to occur within the channel itself . The confluence of higher amounts of C and NO3 – moving into a reduced zone could be the reason that the matrix surrounding the preferential flow channel has higher denitrification rates, while the regions further away from the preferential flow channel have lower amounts of microbially available C and NO3 – . In contrast, residence times are too short in the channel to allow for reducing conditions to develop. The ability of the entire vadose zone to denitrify would depend on the overall surface area of preferential flow paths to the rest of the surrounding matrix in the zone of flooding. Overall, we find that low permeability zones alone or embedded within high flow zones demonstrate highest denitrification rates across all soil profiles. Because the ERT column more closely approximates the heterogenity of our agricultural field site,flower bucket we use this column to demonstrate the impact of hydraulic loading and application frequency on nitrogen fate and dynamics. Simulated profiles of liquid saturation, NO3 – , NO3 – :Cland acetate for the simplified ERT stratigraphy for scenarios S2 and S3 are shown in Figure 9 and A3. It is interesting to note that AgMAR ponding under scenarios S2 and S3 resulted in fully saturated conditions to persist within the root zone only. In comparison, the 68 cm all-at-once application for scenario S1 resulted in fully saturated conditions to occur at even greater depths of 235 cm-bgs . This resulted in the NO3 – front moving deeper into the subsurface to depths of 450 cm-bgs under S1 compared to 150 cm-bgs for scenarios S2 and S3 . Much lower concentrations of NO3 – were found at 450 cm-bgs in scenarios S2 and S3 compared to S1 . Thus, larger amounts of water applied all-at-once led to NO3 – being transported faster and deeper into the profile. Surprisingly, model results indicate 37% of NO3 – was denitrified with scenario S1, while 34% and 32% of NO3 – was denitrified in scenarios S2 and S3, respectively. For scenarios S2 and S3, denitrification was estimated to occur only within the root zone. This was confirmed by NO3 – :Clratio that did not show any reduction with depth for these scenarios. A reason for this could be that acetate was not estimated to occur below the root zone, preventing electron donors from reaching greater depths for denitrification to occur. In contrast, model results for S1 indicate that acetate was leached down to 235 cm-bgs below the limiting layer. Overall, model results indicate that NO3 – did not move as fast or as deep in scenarios S2 or S3; however, the ability of the vadose zone to denitrify was reduced when the hydraulic loading was decreased. The main reason for this was that breaking the application into smaller hydraulic loadings resulted in O2concentrations to recover to background atmospheric conditions faster than the larger allat-once application in scenario S1. In fact, the O2 concentration differed slightly between S2 and S3. Because O2 inhibits denitrification, we conclude that these conditions resulted in the different denitrification capacity across application frequency and duration. In summary, we find that larger amounts of water applied all-at-once increased the denitrification capacity of the vadose zone while incremental application of water did not. However, NO3 – movement to deeper depths was slower under S2 and S3.

Because initial saturation conditions impact nitrogen leaching, we also simulated the impact of wetter antecedent moisture with 15% higher saturation levels than the base case simulation for the ERT profile. Simulated profiles of liquid saturation, NO3 – , NO3 – :Cland acetate for the simplified ERT stratigraphy under wetter conditions are shown in Figure 10. Model results demonstrate that the water front moved faster and deeper into the soil profile under initially wetter conditions for all three scenarios. Within the shallow vadose zone , across AgMAR scenarios, O2 concentrations were similar initially, but began differing at early simulated times, with lower O2 under wetter antecedent moisture conditions than with the base-case simulation. In addition, both oxygen and nitrate concentrations showed significant spatial variation across the modeled column. Notably, nitrate concentrations were 166% higher in the preferential flow channel compared to the sandy loam matrix under wetter conditions, while only 161% difference was observed under the base case simulation . Nitrate movement followed a pattern similar to water flow, with NO3 – reaching greater depths with the wetter antecedent moisture conditions. Under S1, however, at 150 cm-bgs, NO3 – decreased more quickly under the wetter antecedent moisture conditions due to biochemical reduction of NO3 – , as evidenced by the decrease in NO3 – :Clratio, as well as by dilution of the incoming floodwater. In the wetter antecedent moisture conditions, 39%, 31%, and 30% of NO3 – was denitrified under S1, S2, and S3, respectively. For S1, where water was applied all at once, more denitrification occurred in the wetter antecedent moisture conditions, however, the same was not true of S2 and S3 where water applications were broken up over time. This could be due to the hysteresis effect of subsequent applications of water occurring at higher initial moisture contents, allowing the NO3 – to move faster and deeper into the profile without the longer residence times needed for denitrification to occur. Thus, wetter antecedent moisture conditions prime the system for increased denitrification capacity when water is applied all at once and sufficient reducing conditions are reached, however, this is counteracted by faster movement of NO3 – into the vadose zone. Simluations from our study demonstrate that low-permeability zones such as silt loams allow for reducing conditions to develop, thereby leading to higher denitrification in these sediments as compared to high permeability zones such as sandy loams. In fact, the homogenous silt loam profile reported the maximum amount of denitrification occurring across all five stratigraphic configurations . Furthermore, the presence of a silt loam channel in a dominant sandy loam column increased the capacity of the column to denitrify by 2%. Conversely, adding a sandy loam channel into a silt loam matrix decreased the capacity of the column to denitrify by 2%. These relatively simple heterogeneities exemplify how hot spots in the vadose zone can have a small but accumulating effect on denitrification capacity . Note that differences in denitrification capacity maybe much greater than reported here because of increased complexity and heterogeneity of actual field sites when compared to our simplified modeling domains. Another observation of interest for silty loams is the prominence of chemolithoautotrophic reactions and Fe cycling observed in these sediments. In comparison, sandy loam sediments showed persistence and transport of NO3 – to greater depths. A reason for this is that oxygen concentration was much more dynamic in sandy loams, rebounding to oxic conditions more readily than in silt loams, even deep into the vadose zone .

The last two chapters will focus on one project , and the other three will provide a broader account of Brazilian South South cooperation. Here, what is lost in terms of depth is hopefully gained in terms of breadth. Had I focused only on the cotton project, for instance, I probably would not have had a real notion of the heterogeneity and shifting character of this phenomenon called “Brazilian SouthSouth cooperation”, and might have generalized an experience that turned out to be in fact quite particular, even within Embrapa itself. This is due not only to the way I entered the field, but to the way I left it. In other words, it has to do with the highly politically charged character of the phenomena that I am proposing to describe here . As with other ethnographies of developers, many things – important things – had to be either addressed indirectly or left out of writing altogether for ethical reasons. As Rottenburg remarked, differential access to information is itself part of the game in development networks, so there will always be a potential for interference and even harm by the ethnographer’s “external” gaze.20 My transit from field to desk – a step that, when completed, would normally mean the conclusion of the PhD project cycle – has been therefore shaped by a prospect: the reverse path, from desk back to field. In fact,procona flower transport containers I have had a previous experience with an academic publication going back to the field in a way that was, from my perspective, “unfaithful” to it.

I know already of a couple of field interlocutors who have quoted some of my writings about Brazilian South-South cooperation. This dissertation is therefore not a detached account, but, to use Jensen and Rödje’s Deleuzian-Strathernian idiom, a “specific exploratio[n] of multiple concrete interfaces at which … experimentation with the real takes place” . This way, it can be brought into generative connections with other academic works on similar phenomena, and hopefully also with the field: as these authors have further suggested, “if the relation between the explanation and explained is destabilized and rendered flexible, then one’s ambition cannot be to achieve a more or less adequate ‘matching’ of the two. Instead the aspiration must be to create associations that mutually enrich and reciprocally transform each part of the material” . By thus nurturing this dissertation’s relational potentials vis-à-vis both academia and the field in a direction that I see as productive for both domains, I hope it can be a step towards a more robust representation of / intervention on the emerging practical and discursive interfaces of South-South cooperation. This chapter looks at South-South cooperation as an emergent trend within the international development landscape. What was described in the vignette with which I opened the Introduction is not something one would encounter as frequently, say, even ten years ago. Both Brazil and China have been entertaining cooperative relations with various parts of the African continent since decolonization and even before that, but not with the same extension, purposefulness, systematicity, or visibility of today. And even though many of the processes, institutions, and individual actors engaged in contemporary South-South cooperation did exist previously, I suggest that the interfaces into which they are being brought together since the last decade or so are, indeed, emergent.

This claim is based on Brazil’s recent rise as a provider of cooperation, but the growing body of works on other emerging donors indicate that some of the trends I observed may be more generally shared among them. As virtually all commentators, academic and not, of these proliferating global interfaces remarked, the agents and processes that have been brought together under the rubric of SouthSouth cooperation are multiple, shifting, ambiguous, and sometimes contradictory. South-South cooperation is itself a contested term, not only in academia but in the field: various actors and institutions currently struggle with or against each other to codify it and stabilize their own account of what South-South cooperation is or should be. But in spite of the complexity of stakes and narratives, a claim that has been widely shared by those purporting to speak about, or in behalf of, it in Brazil and elsewhere is that it is something different than the development aid provided by Northern donors and multilateral institutions during the last half-century or so. This claim to difference is found both in self-accounts by emerging donors and in views on them by Northern donors and the recipients of cooperation. Difference may have opposite signals: competition or complementarity, positivity or negativity. Thus, one of the common framings of South-South cooperation has been neoimperialism; in this view, emerging donors would be merely reproducing the rapacious intentions and behaviors of their Northern counterparts, and even more perniciously because couched in a cloak of Third World solidarity. Another option is a negative assessment of emerging donors by those who stand by development aid: that through their heterodox and unaccountable practices, new donors would be jeopardizing the good work achieved by traditional aid thus far. A third perspective, which shares the latter’s sympathy towards traditional aid, views South-South cooperation as an embryonic, incomplete phenomenon, that has yet to catch up with the more mature form of development cooperation found in the global North and in multilateral institutions such as the World Bank or UNDP.

Finally, and closing the circle of this four-legged matrix, critics of Northern development aid may see in emerging donors a hope out of the latter’s neocolonial grasp over the global South. Between these poles, in practice there are multiple hybrids and combinations. During fieldwork, the most prevalent views involved the latter two; rarely did I come across manifestations of the first two among Brazil’s African partners. In Brazil and elsewhere in the emerging global South , even official self-accounts do not always fit squarely in one such options. In its multiple manifestations in the various governmental and nongovernmental arms involved in the provision of South-South cooperation, emerging donors’ views on themselves may also span polar ends: ranging from an oppositional, Third-Worldist discourse that they should remain independent from the North and frame their practices against those of traditional development aid , to a conciliatory, North-friendly narrative that South-South cooperation is here to complement, rather than to replace or oppose, aid delivered by traditional donors. Although my interlocutors in Brasília used to be much more explicit about these kinds of self-accounts than those implementing cooperation activities on the ground, I found more or less coherent versions of these two views among all of them – not rarely, ambivalently combined in the same person. The question of difference between South-South cooperation and its North-South counterpart found in the field also characterizes this dissertation’s engagement with the available literature. In the absence of an ethnographically and theoretically robust body of ethnographic works on emerging donors, this chapter’s privileged academic interlocutors will be studies based on development initiatives led by Northern donors or multilateral agencies. Two mainstream currents will be privileged here: works inspired by Foucault’s notions of discourse and governmentality , and actor-based approaches .The debates prevalent in this literature drew attention to three inter-related analytical domains, which this chapter will approach: historical genealogies of development cooperation; organizational architecture and dynamics; and discourse and de-politicization. Section 1 will sketch a brief historical account of South-South cooperation based on its relations with traditional development aid,procona valencia going back and forth between global scales and Brazil’s more situated standpoint. Against the backdrop of this situated genealogy, Sections 2 will set the terms for a discussion, to be pursued further in this dissertation, about whether, and in which sense, would South-South cooperation imply a re-politicization of a phenomenon marked, according to much of the anthropological literature on development aid, by de-politicization. Section 3 will provide an account of the organizational architecture and dynamics of Brazilian South-South cooperation, based on data collected during fieldwork and on secondary sources.

The chapter will conclude by claiming that this emerging phenomenon calls for an analytics capable of attending to open-endedness, ambivalences and contradiction, as well as to the historical density of particular South-South relations. I suggest that generative insights in this direction may be found in discussions on the postcolonial question in Latin America and elsewhere; the next chapter will put some of these to work with respect to Brazil-Africa relations.Brazil and other emerging donors are hardly newcomers to the international development scene. From its early beginnings, the Western development apparatus has included them, but mostly in the condition of beneficiaries of aid. This experience as recipients is relevant for their current transition to providers of cooperation, but this relation is not a simple one to track empirically . Moreover, South-South cooperation provided by individual countries is never an isolated, unidirectional effort, but part of a broader historical tide that has also included other emerging donors. This is a story about a changing world order, about an emerging multi-polar world that would have outgrown the regulatory shoes crafted by the hegemonic geopolitics that spanned much of the twentieth-century. It is a story told by many narrators, including – and claims to North-South opposition notwithstanding – the international development community itself. How would the story of international development, told by so many in the academic literature , look like from the other side of the North-South hemispheric divide? In historical approaches to South-South cooperation, a common way to begin has been with the emergence of the global development apparatus at large and the “making of the Third World” that ensued . From this perspective, SouthSouth cooperation shares Northern development’s two chief, interrelated historical vectors: the emergence of the global multilateral system in the aftermath of the World Wars, within which developing countries participated initially as subaltern parties and recipients of aid; and decolonization in Africa and Asia, which led to the formation of what would become the Third World. It was not until then that broad-based alignments across what is now best known as the global South could emerge as a formal engagement between independent nation-states. Against this broader historical canvass, Mawdsley singled out more particular “drivers or contexts” in her comprehensive work on emerging donors: “socialism, the NonAligned Movement, the United Nations South-South cooperation initiatives, the oil price rises in the 1970s, and European Union expansion” . The last two have little relevance for the case of Brazil, and in the others, it has participated quite differently than other emerging donors such as China, India, or Russia. A loyal, though at times ambivalent, member of the Western block along with most of Latin America, Brazil has been less permeable to the Cold War juggling for allegiances that marked decolonization in much of Asia and Africa.Cold War geopolitics was, on the other hand, key for understanding the early engagements within and between Asia and Africa during decolonization. Besides the former Soviet Union and China, smaller socialist countries such as Cuba, Vietnam and those in Eastern Europe participated in pioneer experiences of South-South collaboration in various domains, from financial to military, from technical to diplomatic . The non-aligned movement was also a direct outgrowth of Cold War politics, but emerging around a commitment not to align with either of the two blocs. If Harry Truman’s iconic 1949 Point Four program is widely referenced in both the academic and the development literature as marking the birth of international development,the 1955 Bandung Conference is often raised as a key historical landmark for horizontal cooperation between Third World nations.Even if the Conference’s original twenty-nine members – all from Asia, Africa, and the Middle East – were not equally committed to neutralism, they closed ranks firmly around the question of decolonization.Both in Bandung and in its sequel, the Non-Aligned Movement, Brazil and most of Latin America participated only as observers. As independences were gradually achieved and most of the original Bandung and non-alignment leaders eventually left power, the politico-ideological character of early alignments across the nascent Third World gradually gave way to pragmatic drives of a geopolitical and economic order . As will be seen, even if foreign aid was not a major theme in the Non-Aligned Movement, the purchase of the latter’s political language in contemporary South-South cooperation, including in Brazil, is remarkable.

If the potential support is not proportional to revenues, then the tangency will deviate so that the group with more political clout receives lower prices. Both of these situations can deviate from the case of the discriminating monopolist which would charge prices based solely on the relative costs of providing service to each group. Rosen, develop a cooperative game model that examines how coalitions might be built for water markets within a district . This model uses an approach developed by Sexton to assess the voting patterns of agricultural production cooperatives . In this cooperative setting, R&S examine if a policy which maximizes the net benefits fora number of individuals that represents the majority in the district will be chosen over another which maximizes the total net monetary benefits to the members of the district. R&S assume that a single popular vote institution is used to transmit political influence to the district’s board and managers.’ The implicit assumption is that political power is in proportion to the institutional allocation of votes. R&S examined the Imperial Irrigation District-Metropolitan Water District sales transactions and how lID farmers decided to accept or reject various sales terms and revenue allocations. R&S surveyed 31 farmers about their farm operations to estimate the net benefits from alternative trading scenarios. They then created a voter-decision model using a pair-wise voting procedure that simulated farmers’ choices based on the expected net benefits to each individual.

The result was that the policy which would have generated the greatest total benefits to district members-a defacto assignation of water rights to individual land owners before transfer-lost to a policy which gave the greatest net benefits to a majority of eligible voters-a combination of conservation measures to preserve water supplies to farms and a distribution of A useful institutional perspective is to compare how the operations and financing of water districts reflect the principles of cooperatives : these districts provide service “at cost” as non-profit organizations; benefits generally are distributed in proportion to use of the managed resource; returns to equity capital are limited and generally gained through directly-related activities, such as selling irrigated crops; and the district is controlled by the member-users, which meshes with the concept of vertical integration of the water supply with agricultural production. Several advantages exist in the cooperative management of input resources . The joint allocation of resources avoids the transaction costs and risks associated with markettype exchange institution, e.g., post-contract opportunism by a party . By extending or avoiding market power, it can encourage development of asset-specific relationships by removing risk of contract breach . And it provides a mechanism for avoiding, mitigating,25 litre plant pot spreading and sharing risk among members . The internalization of allocation decisions can avoid government interference in the exchange institution, e.g., federal reclamation law acreage limitations . The model presented here builds on the three political-economy models that explain district behavior from different perspectives, but rely on a common assumption. The assumption is that members try to influence district managers to choose management policies that distribute benefits in proportion to political power while maximizing aggregate benefits subject to that constraint.

The district’s objective, acting as a cooperative, is to maximize net benefits to all members, but the non-profit constraint means that the district’s “rents” must be distributed among its members indirectly, perhaps through changes in water rates or allocations. This distribution is the function of political power within the district, measured in terms of voting share in this case. Politically, water districts in California are marked by a variety of governance-selection schemes . Most of these are directed through state general district acts, of which there are 38 types; in addition, over one hundred special-district enabling acts were in place by 1994 . Selection of the governing board may be through a vote of eligible persons or appointment by the county board of supervisors. Eligible voters may be residents of the district and/or property owners. Votes may be counted as one-person/one-vote or be weighted by property acreage or assessed value per acre. California law tends to favor landowners in governance procedures . While the popular vote is predominate in older districts in the Sacramento and east San Joaquin Valleys, the property-weighted scheme has grown in use, especially in the west and south San Joaquin Valley served by the newer state and federal water projects where corporate farms, rather than family-owned farms, are more common . Even older districts have switched to land-owner enfranchisement.’ Each of the districts’ management-selection procedures give different incentives to district members and managers. Economic theory leads to an expectation that an assessed-property-value weighted voting scheme would most closely mimic that of a vertically-integrated firm. Agricultural property values reflect the net returns to crops, and to the degree that water application is correlated with land values, the votes would be allocated in proportion to implicit ownership and utilization of the water resource. However, because land values reflect other factors such as soil type and relative market location, value-based voting should not simply follow the same pattern as that for single-product firms.

District “ownership” shares are not necessarily in direct proportion to the value-added from water application, as would be case in a private enterprise where ownership would be based on output value, not input quantities. Acreageweighted schemes reflect a presumption that the amount of water applied per acre is roughly constant across farms and that marginal land values attributable to water use do not vary substantially across a district. This scheme is less likely to match the profit-maximizing interests of the landowners than value-based methods. A popular-vote method tends to divest the district from a solely profit-maximizing objective. Equitable distribution of benefits from district operations become more important. The interests of individual landowner farmers can diverge from that of the district, e.g. in the extra district sale of water rights. Finally, board-appointed districts represent an interesting enigma. In theory, because the district board supposedly represents the interests of the entire county, the decision-making process for the district should be quite divergent from maximizing the profits of those receiving water supplies. However, these agencies are relatively obscure except to those directly impacted, and these boards more likely are “captured” by their customers and reflect their informally-transmitted desires. In summary, it is evident that the motives for the districts can be quite different than the classic assumption of “profit-maximization. ” The various governance rules used by different types of districts, such as voting eligibility and weighting, can undermine some of the principles in cooperative management in achieving efficiency. Stated simply, managers are likely to distribute benefits from operations of the district in proportion to the political strength of its members rather than to economic contribution. Reliance on popular vote rather than property-weighted vote can create a wedge between those defined as members versus users, and benefits may be rebated on a basis different from use. These benefits might extend beyond simply delivering water to reassigning responsibility for water rights, deciding if water sales need approval to protect certain interests within the district, and setting district charges and taxes to achieve economic goals other than efficiency. In general, we might expect if the votes are distributed in proportion to the value of agricultural land,30 litre plant pots bulk then the district will act to maximize the value to landowners. If on the other hand, the electoral selection process uses a one-person/one-vote rule, we might expect that the district will attempt to maximize the value of water-related economic activity regardless of its ties to the land. These action can include maintaining the water resource for tenant farmers who do not hold title to the land but may have significant fixed investments in their farm, and considering local farm-service businesses if they are eligible to vote. An assessed-value-weighted voting scheme appears more likely than a popular-vote system to mimic the prototypical “firm” in economic modeling due to the closer correlation between the governance process and the distribution of benefits from water use. Water sales tend to benefit landowners because the districts’ rights are most frequently tied to the land. Thus, we expect property-weighted districts to be more receptive to selling into a water market than districts with other types of governance structures.

Using some assumptions about how the motives for various district members might differ, we can build a model that assesses how the various political structures might influence the districts’ management decisions. In a property-based voting system, we can assume that the preferred policies will tend to lead to accrual of district benefits in land values. For the popular vote structure, we must identify a proxy for those actions that target benefits towards water related activities. As the voting structure moves away from being directly proportional to the value of water use, we might find that the district’s manager will pursue policies that benefit non-landowners. Landowners are more likely to be focused on the bottom line=-for example, which generates more revenues per acre, growing crops or selling the water. On the other hand, tenant farmers require water to work their land-they are unlikely to receive payment for water sold by the landowner through a district. Local businesses also rely on farming activity, not just income flows to local landholders that might result from water sales. In a popular-vote system, the district may choose to both limit outside water sales so as to maintain farming activity, and to price water in a way that maximizes other related economic activity, e.g., fertilizer and equipment sales. Observing the former is difficult when water markets do not exist for many other reasons such as state policy. However, we may be able to find a suitable proxy for the latter.In the case of tenant farmers, they may be reluctant to plant high-value, water-saving crops due to uncertainty about the their tenure on the land. Orchard crops require several years before they reach maturity and must produce for up to two decades to recover the initial investment. Tenants tend to show higher discount rates than owners, leading to less investment in resource-conserving technologies that are capital intensive . More efficient irrigation technologies generally require sunk investment that can be lost by a tenant if the landowner takes action to stop farming on the land. In response to these risks, tenant farmers would be more likely to grow water-intensive field crops with less-efficient irrigation technologies. To support these practices, the district would lower the per unit price of water so that higher application rates do not cause higher costs, and rely on other revenue sources such as per-acre fees or taxes and electricity sales. Higher property taxes have the added advantage for tenants that the elasticity of demand for land limits the incidence of the tax on rents, i.e., landlords must absorb part of the tax in their rents to stay competitive in the agricultural land market. The existence of sharecropping arrangements reinforces this tendency because landowners often must pay the delivered water charge, which comes out of their rent earnings. Local businesses may prefer two types of outcomes. The first is that crops be grown that require a high level of purchased inputs, e.g., fertilizer or equipment. Field crops generate less employment per acre-foot of water than other crops , which might imply that other local inputs such as farm equipment are utilized to a higher degree in production. The second is that business activity remain at a fairly constant or growing level, and that it be of the same nature year-to year . This gives businesses a greater assurance that they will recover their investment in equipment, knowledge and good will. To serve both of these desires, the district will tend to establish pricing structures that do not penalize water use, particularly if the water is for long-established crops. Again, this perspective encourages support for a two-part pricing tariff in which the per water unit charge is relatively small compared to the fixed or property-based portion.This is done in a broad framework that encompasses a large number of districts. For this reason, the model developed here takes the perspective of a district as the decision-making unit. In this way, we can draw inferences about a broad range of districts while controlling for other factors that may influence their behavior, e.g., source of water, dominant crop type, the types of farming operations.

Oh et al. showed that US consumers are willing to pay higher prices if the fruit were grown locally in a wild friendly farming way that conserve birds.Birds can also play a detrimental role in agroecosystems, specially species of blackbirds , cardinals , doves and parakeets . These species can take advantage of the concentration of food resources in agricultural fields causing reduction in yields .The degree of crop damage may be related to the type of crop grown and other habitat features. For example, in Argentina monk parakeets were found to prefer sunflower instead of corn . According to Fuller-Perrine and Tobin major grape damage in North American vineyards is caused by European starlings , American crows , House finches and Common grackles . Somers and Morris reported that grape damage in Canadian vineyards was related mainly to the presence of the exotic European starling that were found in flocks from 5-200 individuals/daily, although some other native birds were also found but in reduced numbers and just a few times during the season. The same study showed that American crows were also found in large numbers but they did not forage in vineyards. There is spatial localization of bird grape consumption, where upper vine tiers and vineyard edges exhibited more damage than lower tiers and grapes growing at the center of the vineyard . In California, bird damage was estimated to cause profit loss in nuts of 9.6%, in grapes of 9%,best grow pots in berries of 5.7%, and in fruit orchards of 5% . Different techniques have been employed in order to reduce the damage caused by birds to crops.

Berge et al. reported that one effective method was the utilization of electronic devices that emit alarm sounds and distress calls that drive off birds. Although netting the crops was the most effective method to avoid bird damage, it is expensive. The use of nets that cover grapes was proposed as an effective way to control bird grape consumption , but other studies did not find this method to be as effective . Baldwin et al. reported that the most common methods used to avoid bird damage in California were frightening devices, exclusionary devices, and shooting.Agriculture has transformed nearly 40% of the earth’s surface , causing direct effects on wildlife populations, among them birds. Intensive agriculture is considered one of the main threats to biodiversity . Agricultural intensification has been linked with wildlife decline . For example, Karp et al. found in tropical agroecosystems that beta diversity is reduced by 40% under intensive agriculture.Implications of land use change are related not only to habitat loss, fragmentation and lack of connectivity in the agricultural matrix, but direct impacts on species. Global vertebrate extinction has increased significantly since the rise of industrial society when compared to historic and prehistoric times . This process of “defaunation” corresponds not only to a loss of species but also to shifts in species composition, function and interactions that impact the provision of ecosystem services and human well-being . Land use change is one of an interacting group of drivers of extinction . A worldwide multi-taxon study reported strongly negatively impacts on composition and diversity of species by land conversion from primary vegetation to agricultural landscapes, forest plantations, and urban areas . In a global analysis of local diversity affected by increased human population and land use change scenarios from the Intergovernmental Panel on Climate Change. Newbold et al. showed that by the end of the century the within-the same land use of the most impacted habitats species richness will be reduced by 76.5% on average, total abundance by 39.5% and rarefied richness by 40.3% of 47 taxonomic terrestrial groups .

These impacts are more likely to disproportionally occur in countries with high biodiversity but economic poverty although this projection could change if there is sufficient social pressure to revert trends . For example, in Mexico the rate of crop expansion over native grasslands/shrubland in the Chihuahua desert, negatively impacted the overwintering habitat of 28 migratory species in North America . Pan-tropical bird occurrence and abundance decreases along a anthropogenic land use intensity gradient compared to undisturbed habitats . In Germany, models predict that conversion from agriculture to bio-fuel production in order to reduce carbon dioxide emissions will have negative effects on biodiversity. A loss of 10% of the present farmland bird population by 2050 is estimated with expansion of bio-fuel monocultures . In another case study of land use change and bio-energy crops, Everaas et al. modeled the impact on bird breeding of changes from current farms to bio-energy monoculture crops, and reported negative impacts for the majority of species analyzed, suggesting that biodiversity impacts of the spread of intensive monocultures in Germany cannot be mitigated only by conserving 10% of land surface set aside within farms, a current European agro-scheme practice.Under current global scenarios of land use change and scaling rates of per capita consumption, reconciling agricultural production and biodiversity conservation goals is a priority . Different approaches have been proposed in order to achieve these goals. One of the most debated questions is how can we best produce crops to enhance food security while conserving natural areas . Land sharing and land sparing strategies as well as a combination of both have been proposed . The land sharing approach proposes agroecology as a strategy to spatially, temporally, and biologically diversify farms and to increase the value of the agricultural matrix for wildlife habitat . This approach values the relationship of humans with nature and integrates traditional knowledge into management of agroecosystems .

The main contention of the land sharing approach is that low yields from non-intensive agriculture will promote agricultural expansion detrimental to natural areas . However, this yield gap argument has been contested by Ponisio et al. by meta-analysis showing that diversification of organic agriculture can reduce the yield gap between conventional and organic agriculture from ~19% to ~8%. Land sparing proponents have favored high agrochemical input levels aimed at enhancing crop yields and argue that with high production in target crop areas, natural areas land surface will be spared from conversion to crop production . However, current agrochemical use can impact non-target wildlife species. For example pesticide applications in arable farms decrease arthropods that are consumed by Yellowhammer in the reproductive season, negatively impacting their breeding performance . Use of highly toxic pesticides have a direct effect on bird population in US grasslands . Intensive systems proposed by land sparing proponents are characterized by low levels of biodiversity and low heterogeneity of agricultural landscapes . Monocultures can affect the bird species guild in different ways and deplete bird diversity . The land sparing approach assumes that current natural areas will be preserved by preventing further land use conversion to agriculture, but this theoretical assumption does not always hold due to market-driven economic incentives ,plants in pots ideas that promote land use changes linked to the expansion of bio-fuels and land-grabbing initiatives . A third approach for biodiversity conservation in agricultural landscapes proposes an integrated strategy where elements of land sparing and land sharing can be useful for conservation, depending on factors such as the levels of fragmentation, the socio-political conditions, and the level of previous disturbance of the environment . For example, spatial prioritization for conservation in South America shows that when the top 17% of priority areas were analyzed, the land sharing alternative resulted in a better conservation outcome than the land sparing alternative , although in some areas a mixed strategy better matched conservation priorities . In southeastern Australia, Michael et al. found that land sharing strategies were successful for birds, many of which are of conservation concern. However, land sharing had limited effects on conservation of other vertebrates , suggesting that mixed alternatives should be explored .Natural ecosystems provide irreplaceable biotic and abiotic conditions for birds, in particular for highly specialized forest-dependent birds, pollinators birds, migratory species, and endemics . Forest patches and fragments can contribute to higher bird diversity within the agricultural matrix and increase ecosystem services provided by birds . In Madagascar, Martin et al. compared a biological corridor of native vegetation and the surrounding agricultural matrix and found higher species richness in the agricultural mosaic of crops than in the corridor. In particular, some functional groups such as carnivores, terrestrial and sallying insectivores, and granivores were significantly more abundant within the agricultural mosaic, although the majority of these species were generalists and the endemic species remain associated to forest.

It should be emphasized that the agricultural mosaic is defined as a complex diversified system of different crops, where scattered trees, small forest patches, and other secondary habitats support various species. In a fragmented native forest in southern Chile, Carneiro et al. found that isolated native trees supported the abundance of the endemic parakeet within agricultural landscapes. Scattered trees provide key resources for refuge, roosting, nesting, feeding and connectivity within agroecosystems . Riparian corridors within a mosaic of low intensity managed crops provided significant habitat and connectivity for two forest specialist frugivorous birds in Costa Rica . Mangnall and Crowe found in South Africa that retaining native vegetation within a landscape with arable crops could increase bird species richness in comparison with monoculture crops. In the agricultural landscapes of the US Midwest, fragment size of riparian forest was positively related with the occupancy by Neotropical migratory bird species and species richness Forest edges represent ecotones between agroecosystems and native vegetation. These transition zones can host different bird species. In the North American Corn Belt Best et al. , reported that abundance of birds was higher along forest edges adjacent to corn fields in comparison with grassland edges or the center of cornfields. The same study, also stablished that bird abundance decreased in larger corn fields , which fits the patterns of land intensification suggested by Sauerbrei et al. . Similar results were recovered by Terraube et al. , who reported that the bird abundance of insectivores, under story gleaners, resident and migratory birds, cavity nesters and under story nesters increased in the interior of forest edges. Floristic composition and habitat structure were relevant for bird abundance and composition within the forest edges . Ecological and biological traits as well as natural history of different birds influence the adaptability of the different species to anthropogenic environments. For example, Figure 1 shows a number of different species enhanced by agricultural land cover in central Chile, where species composition changed between crop types but also between seasons . Examples of these varying associations of birds with crops, agricultural land cover, management, and ecosystem type are summarized in Table 1.Some bird species have a direct relationship with pastures and are considered grassland obligates, thus depending on agricultural management for their conservation . Cattle stocking at high density directly decrease habitat quality and influence the abundance of arthropods in prairie systems, which in turn influence the availability of prey for insectivorous birds . In a grazing experiment in Florida , Willcox et al. found that along with the loss of structural diversity in more intensively managed grasslands, total richness and abundance of birds decreased in monoculture grassland, although analysis by subgroups showed that some increased with the grazing intensity. Grasslands can also provide alternative feeding habitats, as in the case of the Austral Thrush in central southern Chile. Austral thrushes are considered frugivorous forest birds that, due to conversion of forest to grassland for cattle, were favored by the increase in soil annelids which complement their diet when fruit sources are scarce due to seasonal variation . In the case of the native grasslands of the southern cone of South America, the Pampas, land use change has converted most of the Pampas to rangeland or croplands . In the Pampas, vegetation structure was the main driver of the bird community composition . In terms of grazing pressure, low rates of nest destruction were found in Canada, although the nest destruction was positively correlated with grazing pressure . Silvopastoral systems combines grazing lands with trees and can be considered within the agroecological strategies of improve the agricultural matrix to support biodiversity . In Spain and Portugal ancient cork oaks known as “dehesa” and “montado” forest respectively, are used for different purposes but also can provide biodiversity and ecosystem services . In a “montado” systems, silvopastoral areas with higher heterogeneity supported high richness of bird guilds .

To draw these conclusions, we need to recall the conditions under which the model predicts conflict to occur. First, the model suggests that conflict is likely if aid causes a large shift in the balance of power between governments and insurgents. It should therefore be possible to avoid conflict by making sure that development projects do not affect this balance of power. One way of achieving this is to cooperate with both governments and insurgents in designing the project and delivering the aid. An example of this approach is a recent cooperation of Japan’s International Cooperation Agency with the MILF in extending aid to parts of Mindanao in the southern Philippines. However, while cooperating with insurgents can be a successful strategy in some cases, there are many contexts in which it may not be feasible or ethical. In these cases, we turn to the second condition under which our model predicts conflict: if insurgent attacks have a large negative effect on the probability that the project will be successful. This suggests that violence can be minimized by focusing aid on a small number of projects and heavily defending them. This would make it harder for insurgents to sabotage the projects and thus help deter violent attacks. In addition, it may be desirable to weaken insurgents’ capacity before the start of the project by military means, following a “clear, hold, build” strategy. While more research on the precise mechanism through which development projects cause conflict is needed, our research shows that by combining careful empirical and theoretical analyses,large plastic garden pots we can identify the causal effects of development interventions and use this information to draw conclusions for development policy.It has been over 30 years since China abandoned its large communal farms. Each “farm” had thousands of workers, assigned to production brigades.

The communes were run by inefficient and corrupt top-down management, and state monopolies procured farm production at fixed prices. The communal farming system was a complete disaster, underscored by the 1959–61 famine when an estimated 30 million Chinese residents starved to death. The communes were broken up in the late 1970s in favor of small, family-run plots with profit incentives tied to production and market-determined prices. The economic reforms that started in China’s agricultural sector in the late 1970s then spread to other parts of the economy and we all know the rest of the story. China has enjoyed very strong income growth and has emerged as a main driver of global economic growth. Deng Xiaoping moved China from a top-down planned economy to a market economy, and the results have been nothing short of phenomenal.Today, China produces 18% of the world’s cereal grains, 29% of the world’s meat, and 50% of the world’s vegetables. This success makes China the world’s largest agricultural economy, and it ranks as the largest global producer of pork, wheat, rice, tea, cotton, and fish. In fact, the value of China’s agricultural output is twice the U.S. total. See Figure 1 for China’s share of world food production across various commodities. With only 9% of the global sown area, today China produces about 20% of the world’s food—a miraculous turnaround since the struggles faced by China’s agriculture in the 1960s and 1970s under the collective farms. Despite predictions that China was going to starve the world, instead China has been able to balance its domestic grain supply and demand, with the exception of oil seeds.

Will this continue? After joining the WTO in 2001, China has played a greater role in world agricultural trade. China dramatically increased its trade dependence in agriculture, and it is currently the fifth largest exporter and fourth largest importer of agricultural products in the world. China’s substantial increase in fruit and vegetable production was a major factor behind its agricultural export growth. With imports growing faster than exports during the post-WTO accession years, China reversed its long-time status as a net agricultural exporting country to that of a net importing country since 2004. As expected, with liberalized trade and market forces at work, China increased its imports of land-intensive agricultural products. Most of the increased imports came from soybeans and cotton. Today cotton and soybeans account for 43% of China’s agricultural imports, a very concentrated portfolio. China is the world’s largest importer of soybeans and cotton, accounting for 60% of global soybean imports and 40% of cotton imports. China’s agriculture is supporting a population of over 1.3 billion people today, compared to about 500 million in 1950, on a relatively fixed agricultural land base and shrinking water supply. The tale of China’s agricultural success in meeting this challenge is two-fold. First, China has enjoyed very strong agricultural productivity growth, measured as the difference between growth of agricultural output and the growth of all inputs aggregated. Second, China has poured on farm inputs. China’s annual agricultural productivity growth rate was 2.5% from 1970– 2007, even higher than Brazil’s and much higher than in the United States . At the same time, China’s farmers have intensively applied more chemicals and fertilizer to their crops to try and overcome the limitations of scarce land and water. In the 1980s and 1990s agricultural production in China grew by 5.3% per year, much higher than in other populous countries such as India and Indonesia. Most of this growth came through yield gains rather than through increases in planted area. China boosted grain production by more than 50% during this time period. Grain production in 2010 was 80% above the 1978 level.

Per capita food supply in China rose from 2,328 calories per day in 1980 to 3,029 calories in 2000, a 30% increase in just 20 years. China’s chemical fertilizer use has roughly doubled over the past two decades while pesticide use and mechanized inputs have increased even faster. China has slightly less agricultural land than the United States, but its chemical fertilizer use is now double that of the United States. China uses about one-third of the world’s nitrogen fertilizer and 31% of phosphate fertilizer on its 9% share of the world’s agricultural land. Unfortunately, the strong growth in chemical input use has resulted in considerable agricultural pollution.Let us not forget that China remains a developing country. In China 36% of the population still lives on less than $2 per day and most of these poor are in the countryside. Even though economic reform started in agriculture, non-agricultural economic growth has left the farm population to fall behind. The image we have of the new affluent Chinese consumers buying Gucci handbags in modern boutique shops does not apply to the nation’s farmers. China’s farms remain very small and the work remains highly labor-intensive and difficult. Almost 300 million workers remain in agriculture,raspberry plant pot and most farmers remain very poor, with per capita incomes about $1,000/yr—less than one-third of the average urban income. The proportion of agriculture in China’s GDP dropped from 28.1% in 1978 to 11.8% in 2010. Yet 38% of the labor force remains in agriculture , a ratio that is far too high given China’s level of development. As a result, labor productivity in agriculture remains low. Raising farmers’ incomes is one of the major policy challenges facing China’s policy makers today. This may require relaxing a long-standing policy goal of food self-sufficiency. National food security goals require a very high grain self-sufficiency percentage, and farmers typically earn less money growing grain compared to other higher-valued crops. Between 1981 and 2005, the percentage of people living below the poverty line dropped from 84% to 16.3%. This was part of the success story. But the challenge is that China’s Gini coefficient grew from 29 in 1990 to 42 in 2007, reflecting a strong increase in income disparity within a relatively short period of time. Income inequality in China is now similar to that in Mexico, but the irony is that China is a communist country.Income growth and urbanization, and the resulting changes in dietary patterns, particularly in developing countries like China, have important implications for food consumption and agricultural trade. Urbanization leads to a decrease in calorie consumption per person, but greater demand for processed food products. Low-value staples, such as cereals, account for a larger share of the food budget of the poor while high-value food items, such as dairy and meat, are a larger share of the food budget of the rich. So rising incomes are usually associated with increased demand for meat, horticultural, and processed food products.

In turn, increased demand for meat will result in increased demand for feed grains and protein meals. For instance, China’s per capita incomes have more than tripled in the past 20 years and, as a result, some dramatic changes in food consumption have taken place in that country. Per capita meat consumption has more than doubled in the last 20 years in China. Meeting increased demand for meat and other dietary changes will continue to be a challenge for China. This will require more water supplies because it takes about 2,000 liters of water to produce 1kg of wheat, compared to about 16,000 liters of water for 1kg of beef. Today, much of China’s agriculture is very irrigation-dependent. With 20% of the world’s population and 7% of its fresh water, China faces important water issues. Agriculture uses 76% of the country’s water, but it is facing greater competition from urban areas. In the relatively dry northern region, the water availability per person is only a quarter of that in the south. Yet the north is where almost half China’s population lives, and where most of its maize, wheat, and vegetables are grown. Groundwater is intensively used in the north, but not in the south. This means that water efficiency must be improved in the north. Pricing of surface water and groundwater could play a greater role in the allocation. China’s farmland essentially belongs to local governments, a holdover from the commune era. This means that land cannot be bought or sold by farmers, only leased. This raises a number of policy issues with respect to the transition of China’s agricultural sector towards a more modern industry. Lack of land ownership discourages investment and consolidation into larger and more efficient farms. Land-use rights are now attached to village residency, discouraging permanent out-migration from agriculture and keeping farm incomes low.Agriculture is arguably the sector of the economy most directly exposed to climate and thus likely to be affected by climate change. To date, however, there exists considerable disagreement about the magnitude of potential impacts. Disagreement stems from differences in both methodology and empirical measurement. The recent paper by Deschˆenes and Greenstone , henceforth DG, is an important contribution to the climate impact literature and to the debate on economic methodology. DG’s findings and conclusions hinge on two key factors: how they navigate the distinction between climate and weather, and the metrics they use for measuring both weather effects and economic impacts. In this paper we revisit DG in an attempt to reconcile differences between their work and our own. Climate scientists emphasize the distinction between weather and climate. Weather is what occurs at a particular moment in time – typically, precipitation and temperature. Due to natural variability, weather fluctuates from one hour to another, one day to another, one month to another, and one year to another. Climate, by contrast, is the long-run pattern of weather over time. To climate scientists, therefore, climate change has a very different significance from weather change. A change in weather is inherently short-run, while climate change is a shift in the long-run pattern. Because these are different phenomena, it is not surprising that they also have different economic implications. Differences between weather and climate have implications for the choice of an economic metric. When dealing with climate, the appropriate metric is some measure of the long-run profitability of using the land for agriculture – the equivalent of the permanent income from farming. This is an economic rather than an accounting measure, and it generally has to be inferred through some proxy.

The direct effect of disembodied technical change in the food processing industries, possibly induced by changing output demand, has clearly been MA-saving, even adapted for the conflicting forces from innovation, and rigidities in the agricultural sector, that have affected the virtual prices of agricultural materials and capital.Our goal is to evaluate costs, input demand , and output price behavior in the U.S. food processing industries, and their dependence on various pecuniary and technological forces. A cost function specification recognizing virtual prices, and augmented by an output pricing equation, provides the foundation for this exploration. Such a framework assumes that cost minimizing input demand behavior based on observed input prices and output demand characterizes firms in the food processing industries. The potential for imperfect markets from quasi-fixity and deviations from perfect competition is incorporated through the virtual price specification. The resulting cost structure representation allows us also to characterize profit maximizing output prices and quantities through an equality of the associated marginal cost and marginal revenue. More formally, the technology and cost-minimizing behavior underlying the observed production structure are typically represented by a total cost specification of the form TC, where Y is output, p is a vector of variable input prices, and r is a vector of exogenous technological determinants. Impacts on this cost relationship of changes in components of the p and r vectors,plastic seedling pots and thus on the implied overall costs and input-specific demands, can be derived via 1st- and 2nd-order elasticities with respect to these arguments of the cost function. The ability to reach minimum possible production costs, as implied from such a cost function specification, is often recognized to be restricted by adjustment costs, which severs the equivalence of the observed input price, pk, and its true economic return.

Alternatively, something that looks like internal adjustment costs may stem from increased factor prices due to some other type of input market imperfection. This could arise from, for example, imperfect competition in the factor market, external adjustment costs or unmarketed characteristics.This representation is particularly appealing if the interaction terms from the former model seem uninformative, but an imperfect market gap, lk seems to exist .If instead Zk appears well approximated by pk, or lk» 0, one can reasonably assume that rigidities or other input market imperfections are not binding constraints on, or determinant of, measured cost structure patterns. We have adopted such a virtual price framework as that most consistent with our data, from preliminary investigation of estimation patterns. Evidence was found, however, for deviations between observed and effective or virtual prices for capital and agricultural materials . The virtual price of capital was therefore defined as p*K=pK+l K, with lk¹ 0 potentially attributable to capital rigidities or unmeasured taxation or quality impacts. Various forms for the deviation between pK and ZK=p*K were tested to establish their empirical justification in terms of significance of the parameters, robustness of the overall results, and plausibility of resulting elasticities. The finding that lMA¹ 0 is plausible for a variety of reasons. In particular, if the processing industries perceive some control over MA prices, the marginal than average price drives MA input demand behavior and lMA>0. This is of interest since the potential for processing facilities to depress prices paid to farmers, has often been recognized as a policy concern. In reverse, embodied technical change could imply lower effective prices of agricultural materials compared to their measured values . The variables in the r vector reflecting the industry’s technological base include the time counter t, as well as t2, to represent disembodied technical change trends and further structural change shifts in the 1980s as compared to the 1970s .

A capital equipment to structures ratio, , is also used to represent technology embodied in the capital stock.6 And dummy variables for the different industries, DI , are included to capture fixed effects.Output supply/pricing decisions are also accommodated in this cost-based model by specifying a pricing mechanism that allows for a difference between output price and marginal costs, or average and marginal cost. This extension of the cost function framework is founded on imposing the standard profit maximizing condition underlying output choice, MR = MC , and assuming that any gap between output price pY and MR results from a dependency of pY on output levels; pY. Alternative treatments with lY specified as a function of other exogenous variables were also tried, with no significant impact.10 To empirically implement this model of the production structure of the U.S. food processing industries, we use a panel of input and output quantities and prices we have constructed from the Census of Manufactures, the NBER productivity database, the Bureau of Labor Statistics, and the U.S. Department of Agriculture. In particular, we distinguished cost shares for three materials aggregates – agricultural materials, food materials , and other materials. To accomplish this, we used Census of Manufactures data to calculate the share of each materials aggregate in the industry value of shipments for which cost information is available.These shares were then adjusted in two ways to arrive at our final estimated materials shares. First, in some food industries, the industry value of shipments includes substantial amounts of materials resales – materials that are purchased but not processed before being resold. We subtracted resales from the value of shipments, to better capture manufacturing output. Second, some small establishments are not required to separately report individual materials purchases, but instead report all materials in an “n.s.k.” category.

We assumed that these establishments allocated n.s.k. shipments to agricultural, food, and other materials categories in proportions equivalent to those reported by the larger institutions. Materials input price series were constructed primarily from commodity PPIs from the Bureau of Labor Statistics. In cases where an industry consumed several specific agricultural or food materials, an aggregated materials price index was constructed from the constituent materials indexes, with each price index weighted by its expenditure share in the Census aggregate. In the few cases where PPI indexes were not available, we constructed indexes from average price series maintained by USDA’s National Agricultural Statistics Service. The resulting data panel covers 5-year intervals from 1972 through 1992, for the 40 4- digit SIC industries in the U.S. food processing sector . The remaining data on output and input prices and quantities were taken from the 4-digit manufacturing NBER productivity database, which is often used as a foundation for production structure studies. Although instrumental variables procedures are often used in the literature on which this study is based, to accommodate potential endogeneity or measurement errors in the data, we did not rely on them for a variety of reasons. First, IV techniques require a somewhat arbitrary specification of instruments, which can be problematic. In addition, models of this form are typically estimated with time series data, and often use lagged values of the observed arguments of the function as instruments. But this is not conceptually appealing for our application due to the short time series,container size for raspberries as well as the 5-year gaps between data points. Although some preliminary investigation was carried out to determine the sensitivity of the results to other IV specifications, the results from these models were more volatile and not as plausible as those from the basic SUR model, which was therefore relied on for the final estimation. Our specification of the arguments of the r vector also warrants additional comment. Including ES as a determinant of the cost structure in addition to the standard time trend t initially seemed important for explaining cost and input demand patterns; the ES parameters, interpreted as the impact of technical change embodied in the capital stock, tended to be significant and plausible. When t2 was also included to capture the potential impact of structural changes in the 1980s, the t2 parameters became statistically significant but the ES parameters tended to be less definitive. Both variables thus seem to capture changes in the 1980s – perhaps toward greater capital- or high-tech- intensity of production. Since the ES parameters remained jointly statistically significant, however, they were retained in the final specification. The parameters estimated from the cost-based model specification TC are presented in Appendix Table 1. The dummy terms are not included in the table since there are too many to be illuminating, but they are primarily statistically significant.

The overall explanatory power of the model is indicated by the high R2 ’s for the estimating equations, including the TC equation which was not estimated but was fitted to determine the implied R2 . Also, many parameter estimates that are not individually statistically significant are jointly significant, such as the ES parameters mentioned above.These estimates were used to construct the cost, input demand, and output supply elasticity and contribution estimates from the decompositions outlined in the modeling section. The measures were averaged across the whole sample, and separately for 1972-1982 and 1982- 1992, and by 3-digit industry, to distinguish temporal and industrial patterns. The elasticity estimates were constructed by computing the indicators for each data point and then averaging across the sample under consideration. Statistical significance of these measures was imputed by constructing elasticity estimates instead over the averaged data; values significantly different from zero at the 5% level are indicated by an asterisk. In most cases the significance implications were not data-dependent, although for some estimates the data point at which the measure was evaluated contributed to evidence of significance. To begin our investigation of agricultural materials use in U.S. food processing industries, we first assess MA demand implications from the decomposition presented in the first panel of Table 1 for the full sample . Recall that such a decomposition weighs the estimated elasticities by the observed changes in the arguments of the function to determine their contribution to observed changes in the dependent variable .First consider the elasticities. The largest MA demand elasticity as well as contribution is from its own price. The own elasticity of eMA,pMA = –1.138 for U.S. food processing industries implies MA demand is fairly elastic; pMA increases have motivated a movement up the demand curve to a lower MA demand level that more than compensated for the price change in proportional terms. Based on observed pMA price changes, this provided a negative contribution of CMA,pMA = -0.062% to the overall observed increase in MA use of 0.038 ; other factors outweighed the negative own-demand effect.By contrast, if the indirect implications from the deviation between the effective and observed input prices are taken into account this effect appears quite a bit smaller; p*MA changed by only 0.036% as compared to the pMA change of 0.055%,21 so the total contribution weighted by this price change would be C*MA,pMA = -0.041. The lesser apparent growth in p*MA than pMA could derive from various factors – including augmented quality that is not captured in the measured values – but is inconsistent with increases in market power.That is, l MA appears to capture some form of technical change or productivity embodied in MA, that represents the impact of technical innovation in agricultural markets transferred to the next level of the food chain – food processing.This effect will be evaluated more explicitly below in the context of the indirect components of the t impact within the CMA,t decomposition. All other inputs are substitutable with MA, as is apparent from their positive price elasticities, and the observed increases in these input prices over the sample period thus imply positive shift effects on MA demand that in sum seem to more than compensate for the own price effect. In particular, MA seems somewhat substitutable with both MF and MO, but the contributions of pMF and pMO changes to observed MA demand adaptations are not substantial since the price changes have not been large; CMA,pMF=0.0035 and CMA,pMO=0.016. Rising relative prices of labor and energy – which have been experienced in these industries for most of the recent past – have also had positive effects on MA use, although their contributions are limited by smaller substitution elasticities; CMA,pL=0.012 and CMA,pE=0.004. The statistically insignificant elasticities for pL and pMF suggest that MA-MF substitution is driven more by demand than price impacts. The contribution of pK increases to MA demand is much greater than the price effects associated with other inputs, especially if adjustments in effective pK, p*K, are recognized.

The carryover of fire activity from forest clearing into subsequent years is a cumulative process, such that total high-frequency fire activity in any year represents burning for multiple years of forest loss . For example, elevated fire activity during 2004 in Mato Grosso is the product of deforestation rates during 2002–2005 and high fire frequencies in 2004 for cropland and pasture deforestation. In general, fire frequency is highest for the year in which the deforestation was mapped. For cropland deforestation, fire frequency is similar in the year before and following deforestation mapping. For pasture deforestation, fire frequency is consistently higher in the year following deforestation mapping than the year before detection of deforestation. The number of days on which fires are detected at the same ground location is higher for areas undergoing deforestation than for other fire types in Amazonia, and fires on 3 or more days at the same ground location are almost exclusively linked with forest conversion. During 2003–2007, more than 40% of all high-confidence MODIS fire detections within Amazonia were associated with deforestation. Within this subset of repeated fire detections, container growing raspberries variations in fire frequency suggest that carbon losses from deforestation vary with postclearing land use. Deforestation for cropland may involve burning on as many as 15 days during the same dry season as woody fuels are piled and re-burned to prepare the land for mechanized agricultural production.

Forest conversion for pasture is characterized by fewer days of burning during the dry season, on average, and fewer years of high-frequency fire detections than conversion to cropland. Forests without evidence for cropland or pasture usage following deforestation detection have the lowest fire activity. Higher fire frequency associated with mechanized deforestation suggests greater combustion completeness of the deforestation process compared with less intensive clearing methods. Whereas the first fire following deforestation may consume 20–62% of the forest biomass depending on fuel moisture conditions , piling and burning trunks, branches, and woody roots many times in the same dry season may increase the combustion completeness of the deforestation process to near 100% . Based on published combustion completeness estimates of 20% or 62% per fire, repeated burning during the deforestation process could eliminate initial forest biomass after 5–22 fire events. Combustion completeness and fire emissions from recent deforestation may be higher than previous estimates for deforestation carbon losses. Mechanized equipment can remove stumps and woody roots in preparation for cropland such that both above and below ground forest biomass are burned. Burning woody roots may increase the fire affected biomass by as much as 20% . Fires that burn piled wood are likely to be at the high end of the published range for combustion completeness, given field measurements of high fire temperature and longer duration of flaming and smoldering stages of combustion in piled fuels compared with pasture or initial deforestation fires . High fire frequency for recent deforestation also generates higher total fire emissions compared with previous estimates that assume that a majority of carbon is lost as CO2 from heterotrophic respiration of unburned biomass .

These attributes of fire use for mechanized deforestation in Amazonia challenge the basic assumptions that monitoring deforested area and estimating above ground biomass of tropical forests are sufficient to estimate carbon emissions from deforestation . Failure to consider the evolving roles of post clearing land use on combustion completeness could introduce substantial uncertainty into calculated reductions in carbon emissions from declines in deforestation rates. Findings in this study suggest that average combustion completeness for recent deforestation may be two to four times greater than that estimated for deforestation during 1989–1998 , increasing per-area gross fire emissions for the current decade by a similar magnitude in regions where mechanized deforestation is common. Deforestation for highly capitalized, intensive agricultural production may also reduce the rates of land abandonment to secondary forest compared with previous periods of Amazon colonization, reducing the offset of gross fire emissions from regrowing forests . In addition to further field measurements, we are currently developing a detailed model representing variations in forest biomass, combustion completeness of new deforestation, and offset of fire emissions from regrowing vegetation to more accurately quantify the influence of agricultural intensification on carbon emissions in the region. The use of heavy equipment to manage forest biomass may also change the nature of trace-gas emissions from deforestation. Emissions factors for CO2 are relatively similar for flaming and smoldering phase combustion, but emissions of CH4, CO, and some VOCs from the smoldering stage of deforestation fires are nearly double than that during the flaming phase . The balance between flaming and smoldering phase combustion for 2nd–Nth fires during the forest conversion process is unknown. If emissions ratios do change during the course of the deforestation process as a function of the size or moisture content of woody fuels, the frequency of satellite-based fire detections provides one method to characterize time-varying trace gas emissions for Amazonia. Combining daytime and night-time observations from multiple sensors may better characterize the duration of individual fires to allow more direct interpretation of satellite data for trace gas emissions.Interannual differences in total and high-frequency fire activity highlight trends in both economic and climate conditions across Amazonia.

Concentrated fire activity in Mato Grosso state during 2003–2004 is consistent with peak deforestation for cropland, driven, in part, by high prices for soybean exports . Carryover of fire activity from previous years’ deforestation also contributes to high fire detections during 2003–2005 in Mato Grosso. Thus, reductions in fire intensive cropland deforestation during 2005 do not result in a shift in fire intensity away from central Mato Grosso state until 2006. Regional differences in concentrated fire activity also highlight the role of climate in mediating human caused fires. Roraima, Acre, and Tocantins states in Brazil show dramatic differences in fire activity during 2003, 2005, and 2007. During drought periods in 2003 and 2005, Roraima and Acre had approximately seven and four times as many fires as under normal climate conditions, respectively. The fraction of high-frequency fires was also highest during these drought years, supporting the results from recent studies showing anomalous fire activity and large areas of burned agricultural land and forest in drought affected areas . Future work to verify the detection of active forest burning by satellites is needed to quantify the contribution of forest fires to the regional patterns of high-frequency fire in drought years. In 2007,raspberries for containers anomalous fire activity was driven primarily by low-frequency fires concentrated in southeastern Amazonia and a return to 2004 levels of deforestation fire activity in southeastern Bolivia and the Brazilian states of Mato Grosso and Para´. These examples suggest that even localized drought conditions can spur anomalous fire activity in the presence of anthropogenic ignition sources for deforestation and agricultural land management with important consequences for gross fire emissions. The timing of fires for forest conversion may influence the likelihood of fires escaping their intended boundaries and burning neighboring forest and Cerrado vegetation. Deforestation for pasture contributes more fires during the late dry season when forests in Mato Grosso state may be most flammable after 3–5 months with little rainfall. More even distribution of fires for cropland clearing throughout the dry season may reduce the risk of forest fires. Different timing for cropland and pasture deforestation fires is consistent with management practices for intensive agriculture; mechanized crop production with chemical fertilizers is less reliant on the ash layer from deforestation fires for soil fertility than cattle pasture or smallholder agriculture land uses. However, deforestation fires for both cropland and pasture in Mato Grosso state were common during July and August of 2003–2005 despite local regulations prohibiting fires during these months to minimize the risk of unintended forest fires . Because the most frequent fire detections are indicative of mechanized deforestation and post clearing land use for intensive agricultural production, monitoring cumulative fire frequency could aid the rapid detection of mechanized forest clearing. Improved geolocation and fire detection capabilities of the MODIS sensors compared with previous satellite instruments enable a higher resolution investigation of these patterns of repeated fire activity.

Despite the moderate resolution of the MODIS sensors, information on fire frequencyat 1-km resolution is commensurate with clearing sizes for mechanized crop production in Amazonia that average 3.3 km2 . Active fire information has not previously been merged with land cover change estimates for deforestation monitoring.Our approach to quantify the contribution of deforestation to satellite-based fire activity and characterize individual forest conversions in terms of fire frequency is intentionally conservative. Because of issues of both omission and commission of fires by the MODIS sensors, it is not possible to determine the exact timing or frequency of all fires for the conversion process. We begin with a high-confidence subset of active fire detections to reduce data errors from spurious fire detections over tropical forest . Next, we link deforestation fire activity to high-frequency fire detections, such that fires must be detected at the same ground location on 2 or more days, despite omission of fires from MODIS attributable to fire size , orbital coverage , and the diurnal cycle of fire activity . Despite well-defined changes in land cover, 12% of cropland and 27% of pasture deforestation events in 2004 showed no fire activity in the high-confidence subset of fire detections. Therefore, low-frequency and omitted fires likely increase the fraction of total fire activity in Amazonia linked to deforestation. Because of omission of active fires by MODIS, a more robust method to estimate combustion completeness of the deforestation process may be to combine active fire detections from multiple sensors with other satellite data on deforestation or vegetation phenology to follow the fate of cleared areas over time.A phenomenon that I term REDD Out Ahead is a recurring theme for both REDD negotiators and REDD policy advocates, but for different reasons. For negotiators, REDD out ahead is indicative of a fear that of a lack of coordination between REDD and other elements of the climate schemes. Several of my interview subjects sees this as stemming in part from a lack of capacity for some parties to monitor all streams of the negotiation. A related concern is the unwillingness or inability to assign sufficiently competent staff to the REDD negotiations themselves. On the flip side, some advocates frame the rapid progress of REDD as a point of pride and evidence that the UNFCCC is a viable venue for climate policy. Another set of advocates and scholars, meanwhile argue that the rapid progress of REDD is indicative of the market orientation of REDD and attendant concerns about issues of environmental justice.Every one of my interview subjects spoke of drivers in a way that evoked agriculture. Despite that fact that agriculture is not at present mentioned in the REDD text, the interviewees suggest that the term “drivers of deforestation” is very nearly a proxy for agriculture. Some subjects see this is development as foundational for the future of REDD. Generally speaking, this camp argues that “stove piping” of land use issues is to be avoided. The concern is that this is inefficient for monitoring, and that “you can’t get there from here”, meaning that reducing tropical deforestation appreciably cannot occur without addressing agricultural issues. However, an even larger portion of the party representatives I interviewed see agriculture as what one interviewee described as the “third rail” of international governance in general and in particular environmental governance. “I know we can’t get there from here without agriculture,” one subject told me, “but look, I am as big an advocate for a new treaty as they come and with agriculture in the mix it’ll never happen.” When pressed, the rationale is that the agriculture deforestation link inherently involves grappling with international trade of agricultural commodities. One respondent described this as a, “$100 billion dollar issue.” Among, advocates, however, there is a strong push to get agriculture on the REDD bandwagon. One advocate describes REDD as the last best chance to revive overseas development assistance for agriculture .For several interviewees, the drivers theme heralds a broader trend in decentralizing the principles and content of REDD. These feelings closely cohere with how Boyd describes the emerging polycentricity of REDD.

Average total nitrogen was similar across all hydrologic zones and decreased with depth. The C:N ratio ranged from 8.9 to 11.7 and was relatively consistent with depth in all hydrologic zones . Average KCl-extractable NO3 and NH4 were highest in the flow path zone and generally decreased with depth.There was no significant difference in DNP for any wetland zone between ambient conditions and glucose C-source amendment. However, adding glucose and nitrate significantly increased DNP in all three hydrologic zones . The largest increase was seen in the flow path zone soils at 10 cm . In the upper 10 cm, it is also notable that the maximum measured DNP under non N-limiting conditions was much higher in the flowpath zone. DNP was relatively low and similar for the 50- and 100-cm depths for all hydrologic zones and amendments. Amending the 50- and 100-cm depth soils with glucose or nitrate produced no significant response in DNP. When glucose and nitrate were added there was a slight increase in DNP in a few instances .The first statistical model tested was the most complex and hypothesized that log10 DNP was the result of wetland zone, sample depth, amendment, and soil organic carbon content. The two-way interactions of depth and hydrologic zone, depth and amendment,blueberry pot and hydrologic zone and amendment were also included in this preliminary model. Soil organic carbon content had no significant effect on DNP. There were also no significant interaction effects between depth and hydrologic zone, or zone and amendment.

Depth had a highly significant effect on DNP . DNP was an order of magnitude higher at 10 cm than at the 50- or 100- cm depths for all treatment/wetland zone combinations . There was no significant difference in DNP between the 50- or 100-cm depths. Because of the huge disparity in DNP among depths, the 10-cm depth was separated from the 50- and 100-cm depths for further analysis. At the 10-cm depth, both wetland zone and amendment had a significant effect on DNP, but there was no significant interaction between amendment and wetland zone.With all amendments, DNP showed the following pattern among hydrologic zones: flow path > fingers > uplands . This same pattern was observed with the nitrate removal rates that were calculated from piezometer/pore water depth profiles. The calculated removal rates were similar in magnitude to DNP removal rates.The wetland was highly effective at removing nitrate with an estimated 75% total NO3-N removal efficiency for surface and subsurface flow paths combined . The wetland received 5127 kg of NO3-N from input water originating from agricultural return flows and exported 714 kg of NO3-N in output water during the 6-month irrigation season . Approximately 4122 kg NO3-N infiltrated into the wetland soil as seepage, and of this amount, 547 kg NO3-N was lost as seepage below 100 cm. Thus, 3866 kg of the in flowing NO3-N load was either immobilized biologically via plant and microbial uptake or lost from the system via biotic and abiotic transformations . Patterns of N loading from inflows were similar among zones; increasing in the middle of the season. Outflow N loads were consistently low throughout the study period .

NO3 loads lost via deep seepage were low during the beginning of the season and remained low in flow path and upland zones. In the finger zone, however, a dramatic increase in NO3 seepage loads occurred from late June through September . Seasonal retention efficiencies for NO3-N loads in seepage water were 95, 81, and 70% for the flow path, finger, and upland zones, respectively . A moderate decrease in surface water NO3-N concentration between inflow and outflow locations indicates some NO3-N removal via surface processes , however, high measured rates for DNP in surface soil and significantly lower pore water NO3- N concentrations at 50- and 100-cm depths indicate that subsurface denitrification was a dominant nitrogen removal mechanism . Notably, the NO3-N removal rate estimated via non-nitrate limited DNP values considering all wetland zones was similar to that calculated from the mass balance. Considering all hydrologic zones, NO3-N removal estimated from DNP was 5085 kg NO3-N. This estimate was slightly higher than the estimate of NO3-N removed via the mass balance .Despite the large amount of water lost as vertical seepage , overall NO3-N removal washigh in this restored wetland and comparable to that of other regions with temperate climates. Other studies of wetlands receiving agricultural runoff report NO3-N removal efficiencies ranging from0toashigh as99%.Comparisons of wet land-Ntreatment capability, however, is challenging in agricultural settings, because climate, flow characteristics , N species and N load vary across a wide range of temporal and spatial scales. Wetland characteristics also vary widely . The fact that there was no significant difference between NO3 concentrations at the 50- and 100-cm depths for a given wetland zone suggests that nearly all NO3 removal in this system occurred at depths above 50 cm.

Depth profiles suggest that nitrate removal is uniformly low at depth across all wetland zones . Trends in DNP for N-unlimited conditions were consistent with the nitrate losses observed in piezometer water samples.Denitrification potentials in this wetland were highly variable depending on amendment, depth and wetland environment. DNP measured in this study, ranged from non-detectable to over 15,000 mg NO3-N m 2 d 1 , which spans the range of DNP rates reported by several studies . Average DNP in the main flow path zone was higher than rates reported from wetlands receiving agricultural runoff in other regions, however, DNP in fingers and uplands was similar to that in other studies . Wetland soil properties that influence spatial patterns in denitrifying bacterial communities are pH, redox potential, temperature, soil texture, labile organic carbon, and nitrogen . With the exception of KCl-extractable N these properties were similar throughout the wetland in the upper 10 cm, so it is hard to assess the apparent differences in denitrifier activity based on these soil properties alone . Organic carbon, KCl-extractable N, and pore water nitrate were substantially lower at the 50- and 100-cm depths, so it is possible that denitrifier activity was limited at the lower depths by lack of substrate. The observed lower denitrification potentials at depth are consistent with other studies of constructed wetlands . Some studies in constructed wetlands have found DNP to be spatially uniform . In contrast, we found large differences in space,nursery pots with DNP being higher in the main flow path. Differences in DNP between hydrologic zones at the 10-cm depth may be explained by spatial variability in organic carbon content, differences in redox potential, sedimentation and organic matter quality. Highly variable inflow water fluxes resulted in fluctuating water depths across the wetland, with brief dry-down periods in the finger zones and long dry periods in the upland zones . Higher redox potentials in the upland and finger zones may have contributed to spatial differences in DNP . Many studies report that DNP is more strongly correlated with available carbon rather than total organic carbon . Only organic carbon was measured for this study, so it is possible that there may be substantial differences in carbon availability between the environments that may affect DNP. Also, DOC, which may serve as an important energy source for denitrifiers, was relatively constant across hydrologic zones and soil depths. Sediment deposition in the flow path zone was substantially higher than in the fingers or upland zones, which offers a possible explanation for the disparities in DNP despite similar soil conditions . Areas of active sediment deposition may receive organic matter of different quality compared to that of the native soil from which the wetland was constructed . It is also possible that the sediment, which originated from surrounding farmland, is a seed source of denitrifying bacteria. In fact, studies have shown that frequently tilled agricultural soils in the region have more facultative anaerobes and higher denitrification rates compared to untilled soils .

Since this wetland has only received tail waters for two seasons, it is plausible that we are witnessing the initial stages of recruitment of microbial populations and the associated evolution of wetland bio-geochemical processes. Thus, in older wetlands DNP may be expected to be more uniform. Other studies have shown that spatial variation in denitrification corresponds to patterns in nitrate concentration, increasing in areas of high N loading . Hernandez and Mitsch found higher denitrification potentials in constructed wetland soils where emergent macrophytes were present, when compared to unvegetated constructed wetland sediments. Since vegetation was sparse in both the finger and the flowpath zones, it is unlikely that the relative amount of vegetation had much effect on the observed denitrification potentials. A disproportionately high amount of the nitrogen was removed in the flow path zone compared to the fingers and uplands . This trend was a result of higher nitrate loading rates and significantly higher DNP rates in the flow path compared to other hydrologic zones. The higher mean N-amended DNP rates in the flow path suggest a larger denitrifier microbial population in this zone. The finger zone, although accounting for 40% of seepage, is responsible for the majority of NO3-N lost via deep seepage. This was the result of significantly lower DNP rates relative to the flow path zone and significantly higher pore water NO3-N concentrations at the 100-cm depth . As with any biological process, temperature strongly regulates denitrification rate . Lab incubations were performed at the mean field temperature , which was similar to the mean temperature of the flow path and 0.5 C higher than that of the fingers . Warm daytime temperatures are likely to substantially increase denitrification rate over diurnal timescales.Other NO3-N removal pathways may play an important role in this wetland. NH4 accumulation in pore water, and elevated KCl-extractable NH4 concentrations in the soil at 10 cm suggests that sulfur or ferrous iron-driven nitrate reduction may play a role in nitrogen cycling in this system . Redox potential frequently reached the sulfate reduction level  suggesting the presence of free sulfide. Anecdotal evidence such as H2S smell in groundwater samples, as well as visual identification of iron monosulfides in the sediment verifies the presence of sulfide in the system . At high concentrations, free sulfide is known to inhibit the final two reduction steps in the denitrification sequence, which may drive the reduction to ammonium rather than N2O and N2 . Sorption of ammonium from seepage water to cation exchange sites in the soil may also account for accumulation of ammonium in the upper 10 cm of sediment . Equilibrium with the sediment bound ammonium would result in elevated ammonium concentrations in the associated pore water. Despite the predominately unvegetated main flow path, plant uptake may play a substantial role in nitrogen cycling in this wetland. There may be diffusion of NO3-N from surface water into the upland areas via the shallow water table in the upland zone located approximately at the same elevation as the wetland water surface. The dense vegetation in the upland areas may assimilate a significant amount of N thereby increasing N removal rates.This study demonstrated that soils of recently restored wetlands have the capacity to remove large nitrate loads from vertically percolating water with low risk to groundwater in California’s Central Valley. Bio-geochemical processes in this wetland facilitated significant removal of nitrate inputs from agricultural tail waters. The active flow path of the wetland had the highest DNP at the 10-cm depth under all N amended conditions, and also experienced the greatest sediment deposition rates, nitrogen load and seepage volume . While the flow path had a significantly higher DNP relative to the other zones; the finger environments had a significantly higher DNP relative to the upland environments. These significant differences in DNP between zones may have resulted in the substantial differences in NO3 removal efficiencies, with 95, 81 and 70% reduction in NO3 seepage load in the flow path, finger and upland zones, respectively . Nevertheless, high NO3 removal efficiency in the flow path resulted in a high overall net decrease of NO3 load from seepage water for the entire wetland.

Stream N2O concentrations are often correlated with dissolved nitrogen concentrations ; however, variability in this relationship is often observed between sites . In this study, N2O concentrations were not correlated with microbial community composition, but rather, N2O production was likely elevated in streams indirectly due to high rates of denitrification in response to NO3 pollution. We demonstrate that head water stream microbial communities and ecosystem processes, such as microbial carbon and nitrogen transformations, respond to gradients in land use and stream conditions. Regional differences in stream microbial communities and the observed distance-decay relationships are further evidence that stream communities are seeded from the surrounding landscape. Across geographic regions, microbial community composition varied in streams with high urban, agricultural, and forested land use, and changes in microbial diversity and land use correlated with stream community respiration, linking changes in biodiversity to changes in ecosystem function. Our results suggest that certain microbial groups respond to land use similarly across ecosystems, making them potential candidate taxa to be used in the development of a microbial index of stream conditions.There is much debate about the potential effects of phased reductions in governmental intervention in U. S. agriculture. Unfortunately, growing blueberries in pots there is little evidence that this debate has taken into account the linkages of the agricultural sector with the balance of the U. S. and international economies.

The purpose of the analysis presented in this paper is to give a structural interpretation to the macroeconomic linkages-both forward and backward between the agricultural sector and the aggregate economy; to review and criticize the structural exploration of macroeconomic time series concerning the agricultural sector and the aggregate economy, and to draw out the implications of alternative macroeconomic shocks on the phased reduction of governmental intervention in agriculture. The substantial variation in exchange rates, inflation rates, relative farm prices, and agricultural incomes since the early 1970s has induced a new stream of research on the relationships between macroeconomic policy and the agricultural sector [. In all of these studies, the exchange rate has been recognized as an important determinant of real farm prices through its effects on the trade balance . A series of theoretical and empirical studies on the effect of exchange rates has shown, for instance, the importance of an overvalued currency on U. S. agriculture production and exports . Studies on relative prices and aggregate inflation have supported the hypothesis that the variability in real farm income and prices increases with the general price level variability . At the core of this research is the idea that, if an unanticipated exogenous shock occurs, all the price and interest rate adjustments will happen in some sectors earlier than in others. Assuming prices adjust more quickly in competitive markets than in imperfectly competitive markets, farm prices can be expected to rise faster than non-farm prices, provided of course that agricultural markets are indeed more competitive. Various explanations for these relative price movements have included differences in the supply and demand elasticities of specific products and, more recently, the effects of contract length on the speed of adjustment .

According to Bordo, a change in money supply causes a faster response for farm commodity prices than industrial prices and a faster response for non-durable than durable prices. The existence of nominal influences on real variables in agricultural markets has been tested in a numerous studies . In a more general setting, Fischer has studied three sets of hypotheses linking aggregate price changes to relative price variability: the adjustment cost hypothesis, the rational expectation unanticipated disturbance hypothesis, and the asymmetric price response hypothesis. The first two hypotheses imply that relative price variability is affected by macroeconomic disturbances; the third hypothesis implies that autonomous relative disturbances have macroeconomic effects. Under the first two hypotheses, both price level changes and relative price variability are caused by the same aggregate supply and demand interactions. The third hypothesis is based on the assumption that prices respond asymmetrically to disturbance, for instance, they may be downward inflexible. Under this hypothesis, as Fischer notes , “If the disturbances that move relative prices were primarily supply side, resources should be moving out of the industries where prices have risen towards the industries where prices have yet to fall. If the disturbance were demand side, resources should be moving towards the higher prices sectors.” Hence, differential responses in prices in this case are due to more than price stickiness alone. In Fischer’s empirical work, the available evidence is not totally supportive of the first two hypotheses and the third hypothesis could not be rejected. A number of other studies address the broader macroeconomic scenario. In some cases, this broader perspective includes an examination of the linkages with agricultural commodity prices .

Stemming from Dornbusch’s overshooting models of exchange rate determination, these studies attempt to capture the linkages among exchange rates, money, interest rates, and commodity prices. This work begins with the fixed/flex price specification , modelling the farm sector as a set of auction markets while the non-farm sector is characterized by gradual adjustment of prices. In this framework, agricultural market dynamics is studied, taking into account not only the real demand and supply forces directly related to the farm sector but also the effects of monetary and fiscal policies. The results show that monetary and fiscal policies can have substantial effects on prices and income in the agricultural sector over the short run, whereas sector-specific policies appear to have more significant influences in the long run. Regardless, both sets of policies can have dramatic effects on the dynamic path of the agricultural sector. Unfortunately, the “state of the art” in examining macroeconomic linkages and the role of monetary, fiscal, and commodity-specific policies on the performance of the U. S. agricultural sector is still unsatisfactory. This is, in large part, because not all linkages have been either conceptually or empirically investigated. In particular, the fix/flex specification neglects the structure of commodity-specific policies which limit the downward movement in many agricultural prices. Moreover, the major emphasis in this work has been on what can be referred to as the forward linkages, i.e., those effects that run from the aggregate economy to the agricultural sector. The backward linkages have been almost completely neglected. As noted above, one of the purposes of our analysis is to identify and analyze the backward linkages in conjunction with the forward linkages. Although Gardner might have been correct when he stated, “A fully specified model is not necessary to identify macroeconomic effects upon agriculture; because agriculture is a small part of the general economy ,” there are many other reasons why agriculture could have significant feedback effects on the monetary side of the economy. In particular, a sufficiently large subsidization program for some commodities can have a significant effect on governmental budgets and, thus, fiscal policy. A priori, the fiscal policy effect can in turn influence monetary policy, especially if the monetary authorities’ reaction function is not completely exogenous. With the above motivation as background,drainage gutter we first turn to a theoretical framework that formally incorporates the major features of agricultural policy in the dynamics of commodity, exchange rate, interest rate, money, and manufacturing good markets. This provides the basis for the specification of a vector error correction model with exogenous variables which is empirically estimated in section 3. Based on tests of specific hypotheses regarding identifying restriction as well as forward and backward linkage relationships, a policy simulation model is constructed. This policy simulation model is used to investigate different rates of reduction in governmental subsidization of commodity markets in the face of alternative macroeconomic shocks. From these policy simulation results, a number of concluding remarks and insights are offered in section 6.

The theoretical structural model developed here is a two-sector model in which a number of interactions between the money and foreign exchange markets and the goods market are potentially present. These interactions are both direct and indirect and operate through several different channels. In the analysis, the entire set of interactions are admitted-both direct and indirect and among money, exchange rate, and prices-in a full comprehensive model incorporating all the relevant exogenous variables. The major theoretical features of the model can be’summarized as follows. Manufacturing output is demand determined, while farm output is partly demand detennined and pardy supply detennined where the supply conditions depend on the degree of intervention of the government in agriculture. Prices adjust slowly to changes in money. A balance-of-payment equation detennines the rate of accumulation of reserves as a fraction of the total money stock. Since capital mobility is imperfect, either the capital account or the current account balances can be nonzero in the short run. The monetary authority intervenes on the foreign exchange market in order to keep the rate of depreciation of the exchange rate in line with the domestic trend of monetary growth. Total money supply growth is given by the rate of credit creation and the rate of accumulation of reserves . Price inflation in the two sectors depends on excess demand pressures and on the money growth rate. In the long run, price inflation is equal in the two sectors and is equal to the rate of monetary growth. This is equal to the target rate of credit creation, as well as to the rate of exchange depreciation. Price inflation and output growth in the two sectors, money growth, and the exchange depreciation rate are the endogenous variables. The money stock, the price levels in the two sectors, and the exchange rate level, as well as interest rates, foreign prices , total farm stocks, and government expenditure in agriculture, are exogenously given. Changes in the exchange rate have a direct effect on prices since they imply changes in relative prices. They also have indirect effects, through the foreign exchange intervention rule, since the latter implies a change in domestic supply; a consequent change in income; and, thus, a pressure on prices. Changes in money also have an effect on prices , since they induce changes in domestic demand. Thus, money is non-neutral in the short run. Changes in money supply have an indirect effect also through the change in interest rates, the change in the capital account balance, the consequent pressures on the exchange rate, and therefore on relative prices. Finally, changes in money also have depreciating effects on the exchange rate through the non sterilized foreign exchange intervention.An exogenous supply shock to the entire economy which has stagflation effects, induces changes in the terms of trade and results in changes in the trade balance; in domestic output; and, hence, in money demand. An accommodating monetary policy and a “leaning against the wind” foreign exchange policy will let the changes in prices be fully reflected in changes in money and exchange rates. Sectoral changes in prices, due to autonomous supply shifts, also have effects on money and exchange rates through the trade balance and domestic demand. Within the two-sector model, we incorporate the effects of government farm support programs on the dynamics of agricultural prices in response to changes in monetary and exchange rate policy. The effect of the target price is such that, if the government fully “protects” agriculture, then all downward changes in relative prices are paid back to domestic producers. Thus, changes in market prices are dampened; and the supply reduction measure helps producers adjust to exogenous falls in demand and to alleviate excessive stock accumulation. Reducing excess supply thus has dampening effects on inflation variability. In the limit, if the agricultural output is kept at the market-clearing level, price inflation in the farm sector is equal to general trend inflation. The two policy variables can be proxied by two variables whose actual effect turns out to be even more composite-total farm stocks and government expenditure in agriculture. With no intervention policy in agriculture, following an exogenous reduction in the foreign price of agricultural products we would have a shift of internal demand from domestic to foreign goods, a trade balance deficit, and thus depreciating pressure on the exchange rate. The monetary authority would then intervene on the foreign exchange market by contracting the supply of domestic money in the world market according to the intervention rule.

It is possible that PFAS effects YAP/TAZ localization via cytoskeleton integrity. These connections between adipose tissue maturation and cytoskeletal remodeling are a potential avenue for PFAS perturbation and how it effects lipid profiles and fat development. In obesity, adipocytes are hypertrophic and the expression of the adipokine leptin increases and inflammatory cytokines are increased while adiponectin and lipoprotein lipase are decreased. There are also increases in angiogenesis, immune cell infiltration, and adipose inflammation. These changes are characteristics of insulin resistance, hyperglycemia, dyslipidemia, hypertension, and obesity/adiposity and could be common ground for PFAS associations with obesity in humans. Based on these observations, we hypothesize that PFAS may be mechanistically perturbing the cell cytoskeleton and working through the Hippo pathway resulting in abnormal developmental outcomes in children. In the current study, we have evaluated PFAS’ effects on skin epithelial and adipose derived stem cell lines. We performed in vitro experiments to determine if the cytoskeleton is modulated by PFAS in two types of cells and investigated dysregulation of f-actin and acetylated tubulin. Functional effects on cell survival of both cell types and differentiation of adipose was evaluated in response to PFAS exposure. To investigate if the Hippo signaling effector, YAP, is modulated by PFAS, we quantified YAP expression and localization. Further, we have shown that damaged phenotypes due to PFAS effect the wound healing processes of keratinocyte skin cells and adipose derived mesenchymal stem cells and that some doses of PFAS chemicals induce higher amounts of adipogenesis as determined by lipid droplet staining and qPCR. PFAS effect on the differentiation process of adipose derived mesenchymal stem cells into adipogenic phenotype was also investigated.

Adipogenic differentiation was induced via media,greenhouse ABS snap clamp as completed previously. Adipogenic induction media was DMEM supplemented with 10% FBS and 1% P/S, 500 µM 3-isobutyl-1-methylxanthine , 1 µM Dexamethasone , 10 µg/mL Insulin , and 10 µg/mL indomethacin . To examine how PFAS effected these processes, ASC52telo cells were plated at a density of 25,000 cells/coverslip in 24 well plates on 12 mm glass slides and cultured in adipogenic conditions. After initial seeding in routine culture media, at 48 hours PFOA [100 and 125 µM ] and PFOS [20, 30, 40 µM] were added to well plates. Control media was Adipogenic Induction media. Cultures were carried out for 19 days, at endpoint, all wells were fixed with 4% PFA for 15 minutes then washed x 3 with PBS . Plates were either stored at 4 °C or were immediately exposed to oil-red-o staining for adipogenesis assessment. To assess adipogenesis, lipid content was assayed using Oil Red O staining which marks lipids secreted by adipocytes. ORO staining was completed similar to previous studies. Briefly, a 0.5% lab stock was made up by dissolving 0.2 g Oil Red O in 40 mL Isopropanol . After dissolving overnight, a working stock was made up by diluting the lab stock 2:3 with culture grade water to yield a 0.2% solution in 40% Isopropanol. The 0.2% solution was made up immediately before exposure then filtered before use with a 0.2 µm sterile syringe filter. Each 24 well was filled with 0.5 mL ORO and incubated for 30 minutes at room temperature. After exposure, coverslips were washed 5x with autoclaved distilled water. Phase Contrast imaging at 10x was performed to evaluate adipogenesis and oil-red-o accumulation. For oil-red-o analysis, 3 images were taken per coverslip for each replicate set. For RNA isolations, ASC52telo cells were plated at a density of 500,000 cells/60 mm tissue culture plate then grown up for 48 hours in their routine culture media. At 48 hours, adipogenesis was induced via media and cells were cultured in adipogenic conditions for 19 days with experimental chemical doses. At day 19, mRNA was isolated using the Thermo GeneJet RNA Purification Kit .

All RNA isolations were carried out as outlined by the manufacturer. Assays were completed to assess for adiponectin, leptin, PPARγ, CEBP, and CTGF, using the housekeeping gene GAPdh. Primer sequences given in supplementary data Table 5.1 Primer Sequences used for qPCR. . Quantitative polymerase chain reaction was performed via SensiFAST™ SYBR No-ROX One-Step mastermix from Bioline. All reactions were performed in triplicate. qPCR reactions were completed using a Mic Real Time PCR Cycler at 10 minutes at 45 °C then 2 minutes at 95 °C then 40 3-step cycles of 95 °C for 5 seconds, 60 °C for 20 seconds, and 72 °C for 10 seconds and a melt from 72 °C to 95 °C at 0.3 °C/s. For quantification of mRNA, n = 4. Following culture, coverslips were fixed and permeabilized in place for 20 minutes via 4% paraformaldehyde and 0.25% triton x 100. After fixation, coverslips were washed with PBS x 3 and either stored at 4 °C in PBS or blocked and stained immediately. Samples were first blocked for one hour then stain solution of primary antibodies was added . All stain solutions were made up in blocking buffer except DAPI which was made up in 1 x PBS. Primary antibodies and chemical stains used include: YAP-1, Acetylated Tubulin, Ki67, Phalloidin, DAPI ; antibody specifications given in supplemental data Table 5.2. Coverslips were exposed overnight at 4 °C to primary stain solution then removed, washed x3 with 1x PBS, then exposed overnight to the secondary solution . DAPI was used to mark nuclei and coverslips were exposed for 20-30 minutes at room temperature in 1x PBS, after initial staining was complete. All coverslips were mounted to glass slides using gelvitol allowed to dry, then cleaned with 70% ethanol prior to imaging. Confocal imaging was performed using a Leica TCS SPEII confocal, sCMOS camera attachment. Imaging parameters remained the same for each coverslip in order to compare intensities; each coverslip was imaged using a 20-25 position tilescan and a 1 micron voxel size. Confocal volumes were assessed via custom algorithms designed in MATLAB . Briefly, maximum projections of each tile-position per sample was filtered and segmented which enabled antibody intensity quantification and cell colony health evaluations.

YAP intensity at nuclei and cytosol was quantified in N/TERT-1 and ASC52telo and the number of nuclei per sample was also quantified as an indication of cellcolony health after PFAS exposure. For ASC52telo cells, Ki67 was quantified at nuclei as an indication of proliferation. To evaluate dysregulation of the cytoskeleton of N/TERT-1 cells, expression of phalloidin and acetylated tubulin were quantified using concentric annular rings. Cells were identified using the phalloidin stain then two regions were indicated. A peri-nuclear region and a peripheral nuclear region was identified for each cell and the intensities of phalloidin and acetylated tubulin were quantified within the segments. For all analysis, each experimental condition quantification was based on at least 20 positions per coverslip, intensities were averaged per position per coverslip. For all analysis of confocal images, n = 3 for N/TERT-1 cells for each timepoint and n = 4 for all ASC52telo cells for each time point. For quantification of adipogenesis,snap clamps ABS pvc pipe clip custom MATLAB algorithms were written to assess pixel area of ORO present in each control and dosed coverslips. Three phase contrast images were taken per well; cell coverage and ORO content was determined via image segmentation and averaged for each sample then ORO content was normalized to both the cell coverage of the sample and to the control of each experiment group . PFAS chemicals have stable and bio-accumulative properties which makes them particularly dangerous to biological membrane structures and to the environment in general. Previous work has shown that higher maternal serum concentration of PFAS are associated with decreased birthweight but increased adiposity in infants and in pediatric/young adults, but the mechanism of these changes and toxicity of PFAS chemicals are still largely unknown. Work in animal models has shown that PFAS chemicals have toxic effects and that in some cases these follow nonmonotonic responses. Generally, there is a discrepancy in research doses of PFAS and environmental exposure and detection of PFAS. The U.S Environmental Protection Agency set federal drinking water guideline limits for PFAS at 70 ng/L but, as of 2019 only seven states developed guidelines varying from 13-1000 ng/L. Several states do not have any guidelines at all or only have guidelines for one of many PFAS chemicals. Although the PFAS doses administered in this work are higher than the limitations set , the bio-accumulative properties of PFAS are an important consideration. Guidelines set by the EPA cannot account for bioaccumulation and only apply to drinking water even though humans are exposed to PFAS through many avenues including high amounts from contaminated aquatic species. Thus, there is a mismatch between what guidelines say are safe to consume and what humans are actually consuming or being exposed to. Further, bio-accumulative properties of PFAS chemicals are difficult to model in vitro and hard to discern in vivo because of environmental and body variability.

In the experiments completed here, samples were given the same doses for each time point and were only dosed a single time. For example, the 72 h time point experiments did not get exposed to more PFAS toxicant than the 24 hr time point, but the cells were exposed longer. For the adipogenesis assays, cells were exposed to PFAS at every media feeding, and therefore may have modeled bio-accumulation in a different way than the N/TERT-1s and undifferentiated ASC52telos. To help understand underlying mechanisms of PFAS toxicity in human cells, we studied PFAS effects on cell monolayers. The data presented here show that PFAS effects cell and colony health, as determined by nuclear counts . Interestingly, ASC52telo cell monolayers that were exposed to PFAS remained stable 48 h after exposure and there was not a significant difference in cell number. To understand if PFAS had detrimental effects on proliferation of ASC52telos, we quantified the proliferative marker, Ki67 but concluded that these doses of PFOS and PFOA do not have significant effects on proliferative capacity of ASCs either. However, in agreement with past literature that investigated PFAS effects in the African clawed frog, we show that PFOS and PFOA treatments induce significant declines in cell number of N/TERT-1 cells, and that these declines are greater at longer time points . Additionally, we similarly show that higher PFOS doses produce the greatest cell decreases but our results from PFOA exposure do not follow nonmonotonic relationships as previously shown in the African clawed frog cell monolayers. Importantly, the high dose of PFOS used here is similar to the frog study where the high PFOA and PFOS dose was 10 µM. However, the low dose used for both chemicals from the frog study is not similar to our PFOA doses . More investigation is required to understand if low doses of PFOA produce nonmonotonic effects in human cells. PFAS chemicals have been found to disrupt f-actin, microtubules, and gap junctions of the cell cytoskeleton. We have demonstrated that PFOA and PFOS disrupt the cytoskeletal components, acetylated tubulin and f-actin, in two human cell lines. Increased intensities and shifts in expression of acetylated tubulin and f-actin support cytoskeletal disruption by PFAS that has been reported in other studies. As seen through f-actin fibers , there were also differences in N/TERT-1 cell edges with increased presence of filipodia and prominent protrusions. It could be argued that these cytoskeletal changes are largely due to cell death and colony disruption due to PFAS toxicity, but we have demonstrated that there are cytoskeletal disruptions in ASC52telo cell lines as well. ASC cell lines were resistant to the cytotoxic effects of PFAS exposure and the number of cells and their proliferative capacities did not change after 48 h of exposure. Additionally, the cell death at 24 h seen with the high dose of PFOS did not correspond with radial distribution changes of cytoskeletal components. It is likely that cell death does play a part in the cytoskeletal disruption since colonies themselves are disrupted, but it does not seem to be the only mechanism here. PFAS likely perturbs the cytoskeleton independently of cell death, but this mechanism of action still requires more investigation.Disruption has been demonstrated through actin filament remodeling, central actin stress fiber formation, microtubule and gap junction disorganization, and formation of lamellipodia and filipodia structures at cell periphery. PFOS has been explicitly linked to disruption of blood testi barriers established by Sertoli cells in human and animal studies and thus, accumulation of testicular PFOS.