Tag: hydroponic gutter

One advantage of this process-based approach lies with its reliance on simple regressions

Several California crop disease climate models are in development and are available, including fire blight , scab , alternaria leaf blight , and brown rot . For the farmer, potential adaptation strategies for pests include choice of crop, growing season, manipulative cultural practices, fertilization, pest control, and irrigation, or a combination of these , many of which are currently used to control weeds in agriculture. Yet, there are often trade offs involved that can benefit pests as well . An effective adaptation plan depends on accurately casting predictions, but such predictions are difficult when the impact of undesirable organisms is based on a complex network of interacting factors. Maladaptation can result in negative effects that are as serious as the climate change-induced effects being avoided . Nonetheless, two endeavors stand out as productive methods of ultimately reducing the impact of invasive plants and weeds in California’s changing climate: an increase in our understanding of interactions in an ecosystem context and increased vigilance. Though many competition experiments have been conducted on the effect of rising CO2 on weed-crop competition , both our understanding of how such effects change in an ecosystem context and how such an effect interacts with other aspects of climate change is rudimentary and is insufficient to formulate respectable predictions in California’s future climate. This is further confounded by uncertainty associated with future precipitation patterns and those of El Niño events in California. As a second adaptation, increased vigilance will serve to identify new invaders early, thus dramatically increasing the potential for successful eradication . In terms of increased vigilance,nft hydroponic the “guilty until proven innocent” approach in which each threat is assumed to be dangerous, shows promise.

Where resources are limited, likely problem areas should be targeted, such as disturbed habitat, especially along roadsides and other dispersal corridors, and points of entry. The impact of climate change on pest and disease outbreaks is difficult to predict because it involves changes in both the vigor of the predator and the vulnerability of its prey. Plants do not experience climate change alone, but as part of a wider ecosystem incorporating their pests, pathogens, symbionts and competitors . Although arthropod pests and weeds do interact with each other, strategies aimed at managing one or other of these classes of threats, rarely consider such interactions . Furthermore the great diversity in commodities produced in California, coupled with the abundance of natural vegetation and weeds can provide an important refuge for pests and diseases causing microbes to survive in, at times when their primary crop host plant may be absent. Species with small geographic ranges are more vulnerable to climate change than widespread ones . This is also true of specialist versus generalist pest species. One possible adaptation is to modify planting dates or the selection of cultivars that are resistant to emerging pests and disease causing microbes. As with weeds this dictates the need for vigilance and accurate predictions of pest/disease outbreaks. Implementation of multifaceted pest and disease management strategies such as those applied in IPM will likely enhance the adaptive capacity of producers in a changing climate. Many of the strategies currently used to control disease and pest outbreaks will likely be successful in the climate of the future. Human responses to climate-induced pestilence need to be adaptive and inventive. Agricultural pest control is already a complex and expensive endeavor. For example, increased pesticides are an obvious adaptation; however, this approach has many drawbacks .

When combating Pierce’s disease, for example, in addition to conventional methods such as inspection, pesticides, and host removal, other technologies that are being employed to better control the disease in California, including biological control, sequencing the pathogen genome , and identification and breeding of disease resistant vines . In order to buffer against the unknown interacting effects of climate change, bet-hedging strategies should be used that reduce host pools such as maximizing spatial and temporal crop intra-specific genetic variation . The judicious use of genetic technologies may also prove important in stemming invasions and epidemics by adding to our range of available tools to deal with such challenges. Issues of precipitation are critical. A warmer drier California will likely have a very different pest, weed and disease landscape than a warmer wetter California. Furthermore, research is needed to understand the effects of climate change on the ecology and evolution of agricultural pests. The effects of climate variability on coevolution, virulence, and resistance to control methods are at best poorly understood. For example, does the efficacy of taxon-specific chemical control shift, if at all, in warmer and/or more variable environments? This question is important across all taxonomic levels, from vertebrate pests to microbial pathogens. Changes in competitive balance and trophic interactions are difficult to predict for future climates. Nevertheless, field experiments can be conducted across existing climate gradients representing current and future conditions. Such studies are lacking. Landscape surveys are also instructive in pointing out the value of non-crop habitat in pest control, and in determining spatial and temporal gradients that affect pest distribution . The effect of higher temperatures on overall abundance of herbivorous insects remains unknown in the absence of equivalent data of their natural enemies . Furthermore, efforts to link information specific to California weather to disease and pest outbreaks are limited in their number .

Concerted efforts are needed to monitor and compile data, including historical records. The development and validation of prescriptive control models depend on these data. Currently, climate disease models in California are developed on an as-needed basis with temporary funding often provided by private agricultural interests . Hence, no long-term efforts or programs exist. Increased development is necessary in the use of continuing programs such as the disease warning systems recommended by Wu et al. . Long-term sharing, coordination, and modeling of pest outbreak and environmental data among the diverse climate regions within California would greatly improve our understanding and ability to prepare for, adapt to, and mitigate against future pest risks and disease causing agents. Pests and pathogens that may become significant in California agriculture need to be identified and appropriate quarantine and inspection measures implemented to avoid introduction. Looking to other regions where the climate is similar to that predicted for California in the coming century will also likely be instructive.Land use refers to the management regime humans impose on the biophysical attributes of the earth’s surface. Temperature or rainfall patterns associated with climate change may alter land use and land-cover distributions ,nft system and consequently basic patterns of productivity, stability, and sustainability in agroecosystems . Conversely, the effects of human-induced greenhouse gas fluxes and C sequestration that is attributed to land use and management can, in turn, impact the rate and magnitude of climate change . For example, cultivation of forest and grassland soils accounts for approximately 25% of the net loss of C in the United States, while N fertilization, no-till farming, and grassland restoration have only slightly reduced these losses . Issues of agricultural land use change are particularly interesting in regions with Mediterranean-type climates; they have typically experienced high population growth, urban expansion, and decreasing self-sufficiency in terms of producing their own food, due also to the export value of the many specialty commodities they produce. In California, these issues raise questions related to the sustainability of agriculture, both economically and environmentally. Given the potential growth of California’s population to 9 million people by the end of the century, urbanization is probably the single largest factor driving land use change in California’s agricultural landscapes, farmland loss, and the increasing utilization of wetlands and riparian corridors that serve as wildlife corridors .

Urbanization could result in a loss of 35% of the prime agricultural land in San Joaquin Valley counties, and much of the remaining agricultural land in coastal counties, even when climate change is not considered in the projections . This section will 1) introduce the approaches commonly used to assess climate change effects on land use, 2) discuss the fundamental drivers of land use change, and 3) evaluate knowledge gaps in current mitigation and adaptation strategies for climate change-induced land use shifts in California.Climate change impact assessments commonly employ a hierarchy of models which, ideally, are integrated to simulate the most important processes, interactions, and feed backs in the systems. At the top of the hierarchy are Global Circulation Models , which simulate global climatic patterns on a grid with cells sized between 2 and 9° longitude and/or latitude and several vertical layers thick. Results from GCMs are then used as inputs to biophysical models, which also rank at the top tier of the hierarchy. Outputs from biophysical models are subsequently used as inputs to economic models at, for example, the farm level . Models at the regional scale are more suitable to estimating climate change effects on land use. While some GCM predict gains of 20-50% in potential agricultural land for North America , regional models provide projections at greater resolution and detail. Regional models have forecast that certain crops will be forced to shift out of their current geographical range due to increasing temperatures , but these losses in productivity may be partially offset by increased productivity from increased CO2 levels . Other crops especially C4 plants might suffer lower yields due to elevated atmospheric CO2 levels , though California produces few C4 commodity crops. As Section 6 points out, less is known about how temperature and CO2 concentrations affect key developmental phases of horticultural crops, and thus their vulnerability to climate change. Climate analogs can provide some insights into land use change. Using the hot, dry decade of the 1930s as an analog of the possible climate that might occur in the Missouri, Iowa, Nebraska, and Kansas region as a consequence of climate change, Easterling and Apps modeled crop responses. They found that farm management changes and slight increases in productivity of some crops, for example, irrigated wheat, could eliminate 80% of the negative impact of the analog climate, thus minimizing potential land use change. In California, an analogy of climate change, the drought of 1987-1991 demonstrated that farmers increased their reliance on ground water, adopted water-conserving technologies, reduced water use per acre, moved away from water intensive crops, and fallowed more land . The drought instigated the official approval of water trading and demonstrates how extreme events can trigger rapid changes in land use and social institutions that increase adaptation to climate change. Different approaches have been used to predict climate change impacts on the agricultural landscape, sometimes resulting in very different outcomes. The first approach is a process-based one that arbitrarily or synthetically forecasts a specific climatic change by varying temperature, precipitation, or another model parameter and is likened to a simple sensitivity analysis .Some weaknesses of this approach include 1) the utilization of significant amounts of primary data that are constrained in time and/or space; 2) requisite stable equilibrium conditions; 3) omission of changes in crop physiology and ecosystem productivity, adaptive human behavior, and land use; and 4) neglect of interactions with land use and responses to environmental change . The California SWAP/CALVIN model is similar to this approach, and it predicts relatively feasible changes in terms of crop management and land use change to maintain crop productivity . A second approach models the responses of crops and farmer behavior based on extrapolation of responses of varying climates observed at other sites to the system of interest, and does not necessarily consider unique adaptations that may increase success during transition to a new climate regime . This latter approach is more akin to the approach of Hayhoe et al. . In this case, predicted effects of climate change on wine grape production are more negative than what would be indicated by the SWAP/CALVIN model, suggesting more problems associated with adaptation, and greater changes in land use patterns. Thus, different potentials for land use change emerge from different modeling efforts. More work is needed to improve the accuracy of modeled forecasts of climate change, and to produce results that are accessible and will allow a wide range of user communities in agriculture to adapt to climate change.

Public land ownership is highest in the mountain and desert regions

Today’s agricultural bounty consists of hundreds of commercial agricultural commodities and products sold in every conceivable form at markets ranging from local roadside stands and farmers’ markets to distant markets around the world.The challenge to California farmers and ranchers has always been to match available, and often limited, physical, human, financial, and managerial resources to produce and market alternative outputs chosen from a long and constantly evolving set of potential agricultural commodities and value-added products. Investment and management decisions often involve the integration of production with other economic activities. The highest and best use of resources available to California’s agricultural decision makers requires frequent re-examination of the criteria of the numerous possible uses that are legally permissible, physically possible, financially feasible, and maximally productive. In the dynamic setting of California agriculture, changes are frequent, and often dramatic, as producers and marketers recurrently assess alternatives and make decisions that change important features of the state’s agricultural sector. A half century ago, University of California Dean of Agriculture Claude B. Hutchison in his preface to the book California Agriculture noted the difficulty of measuring the diversity of agricultural production in California even then. He compared the existence of 118 distinct types of farming areas in California in 1946, to substantially lesser numbers in other important agricultural states: 8 in Illinois, 12 in Kansas, 20 in the huge state of Texas, and 25 in Pennsylvania,nft system the state with the next highest number of farming areas. He also noted that only 6 percent of California farms had been classified by the 1940 Census as being general field crop and livestock farms of the sort characteristic of the Midwest Corn Dairy Belt.

“The other 94 percent are distinctly specialized farms, farms devoted largely to the production of a single commodity…Such concentration of effort or specialization calls for outstanding technical and scientific knowledge as well as familiarity with good business methods and procedures” . The developments of the past half century have accelerated greater diversity in types of farming and number of commercial commodities or products. This chapter portrays some of the current dimensions of the state’s diverse agricultural sector by first discussing the characteristics of the major agricultural production regions of California. Natural endowments and man-made infrastructures, in part, determine the nature of agricultural activity within each of the regions. Comparative advantage varies from region to region, and many crops are grown in several regions for reasons of temporal and geographical diversification. A second section discusses the changing composition of agricultural production from extensive to more intensive, higher investment, and higher valued crops. Finally, in the third section, a discussion of the state’s “Top Twenty” agricultural commodities gives better understanding of the nature of agricultural production in California. Nevertheless, the following pages, constrained by time and space considerations, are obviously nothing more than a brief introduction into several ways of examining the diversity of California agriculture.Landforms, hydrography, and climate primarily comprise the physical resources available to farms, ranches, and agribusinesses. Augmented by inputs of production capital, management, and labor, and by private and public investments in institutions and infrastructure, the physical resources importantly characterize the state’s agricultural production regions. California is a large state, the second largest in the conterminous United States. Within such a large geographical area, variations in physical resources are often extreme. For example, normal annual precipitation ranges from only 2.75 inches at Imperial in the southeastern comer of the state to over 100 inches of rain in the northwest corner of the state and at higher elevations in the Sierra Nevada and Coast ranges.

The availability of natural rainfall and snow melt fostered early irrigation development on the western slopes of the Sierras. The uneven seasonal and geographical distribution of surface water led to early private, and later governmental, investments in storage and conveyance systems. Both the highest and lowest elevations in the conterminous United States are found in California—within 75 aerial miles of each other.Climatic regions range from hot desert to alpine tundra. While most of the state’s population and much of its agricultural production occur in areas characterized by a Mediterranean climate, many of its agricultural areas in the San Joaquin Valley and in southern interior areas are located in steppe or desert climatic zones.Growing seasons range from year-round frost-free areas along the coast to relatively short seasons in higher elevation mountain valleys. The more than 700 soil series in California also reflect vast variations in age, parent material, and natural vegetation, in addition to the influence of climate and topography. Residual and transported soils vary greatly in depth, permeability, water-holding capacity, and nutrient-supplying capacity. For these and other reasons, the great variation in the physical resources available to agriculture across the state is more than sufficient to bear out the “any-crop, somewhere” maxim. Figure 1 shows California agricultural production regions delineated along county boundaries.For the most part, these regions are characterized by different resources and land uses, with the exception of valley versus mountain-type lands found along the boundary between the Central Valley and the Sierra Nevada region.8 Forty-nine percent of California lands is in public ownership, most of it controlled by the federal government .Conversely, the most agriculturally important regions have the highest private ownership levels, ranging from 71 percent in the San Joaquin Valley to about 80 percent in the Central Coast and Sacramento Valley regions. Statewide, 28 percent of the land area is in farms. Of the land in farms, 39 percent is cropland; and of the land in cropland, 81 percent is irrigated. The 1997 Census tallied 74,126 farms, which averaged 374 acres in size and sold an average of $311,000 of farm products per farm.

The size and value-of-sales statistics include both small, part-time and larger full-time farm units.Among regions, the highest average per acre sales were reported for the more intensive South Coast and South Desert subregions and the San Joaquin Valley region. The following discussion includes brief descriptions of California’s agricultural production regions as denoted in Figure 1 and summarized in Table 1. Regional values of agricultural production are based on 2001 crop reports prepared by County Agricultural Commissioners. Regional production is distributed among five categories: Field crops, Fruit and Nut crops, Vegetable crops, Livestock, poultry and products, and Nursery, Greenhouse and Floriculture crops .Consisting of the nine counties in the three northernmost production regions, the North region is in the main a relatively unimportant agricultural area of the state, even though it contains about a fifth of the state’s land area. More than half of the land area is in public ownership, and private forestry is a significant land use. Relatively small proportions of land are in farms , and of that land only 20 percent is cropland. Cattle and sheep operations, the most important component of the region’s overall agricultural economy, utilize a combination of owned land, a portion of which is typically devoted to hay or irrigated pasture production, and leased public rangelands, commonly used for summer grazing. Some dairying is still found in coastal areas. Field crop production,hydroponic gutter which includes rangeland and pasture for livestock, contributed 34 percent of the value of production in 1995, and livestock production itself amounted to another 28 percent. Some highly productive farming areas include the North Coast grape growing region in Mendocino County and the Tulelake district and mountain valley areas of the northeast, where potatoes, alfalfa hay, malting barley, durum wheat, and sugar beets are regionally important cash crops.This production region consists of a number of highly productive areas with coastal climate and fertile soils devoted to high-valued vegetable, fruit, and nursery production, as well as less productive dryland farming areas, all of which occur in relatively close proximity to the north-south Coast Range of mountains. Since early settlement, the Central Coast has been a very important agricultural region of the state.However, significant acreage has been lost to urban development as California’s population has grown. For example, farmland in the once highly productive Santa Clara Valley has been almost totally displaced by urbanization; having lost its historic reputation for tree fruit and nut production, the region is now widely known as the “Silicon Valley,” a center of the computer and electronic industries. Because of agreeable climate and other coastal amenities, pressures for urban development continue in many locales. Despite the inclusion of the important Napa and Sonoma County wine grape growing areas north of San Francisco, and the important vegetable and wine grape production areas of the Salinas Valley and Santa Maria and other coastal areas of the south, only 22 percent of the Central Coast land area is in crop land.

About half of the cropland is irrigated. High valued vegetable production, mainly in Monterey, Santa Cruz, San Benito, and San Luis Obispo counties, contributed 53 percent of the value of production from the Central Coast production region in 1995; fruit and nut crops contributed 23 percent. Major vegetable crops include almost all of the vegetables from A to Z .Wine grapes, strawberries, and raspberries are the major fruit crops. Expansion of high valued production has exacerbated surface and groundwater supply concerns. Producers in this region are highly specialized and often use very sophisticated technologies in production and post-harvest activities. Nursery products are important in several of the counties. Dryland farming and livestock activities on the more extensive farming operations contribute only a minor portion of the region’s value of production.The northernmost part and the smaller component of the Great Central Valley, the Sacramento Valley has the highest proportion of land in private ownership of any production region of the state. While urbanization pressures are substantial in the southern portion of the Sacramento Valley, most of the region continues to be heavily dependent on agriculture. Eighty-two percent of Sacramento Valley cropland is irrigated. Irrigation water sources include private and cooperatively developed surface water supplies along the western slope of the Sierras, riparian sources along the major rivers, e.g., the Sacramento, Feather, Yuba, Bear and others, and more recent additions of federally developed water supplying the western valley via the Tehama-Colusa Canal. The Sacramento River and its tributaries are the initial components of the conveyance system for federal and state water systems which, from the Delta southwards, delivers surface water via pumping plants and canals to the San Joaquin Valley and Southern California for agricultural, municipal, and industrial uses. Groundwater sources are also significant. Cooler winters, higher rainfall, and less productive soils than the San Joaquin underlie the continued importance of field crops in the Sacramento Valley. Rice is grown in areas with more impervious basin soils; both wheat and corn are included in irrigated crop rotations; and alfalfa, dry beans, sunflowers, safflower, and vine seeds are among other important field and seed crops. Field corn is grown extensively in the Delta. A variety of fruit and nut crops—mainly almonds, peaches, pears, prunes and walnuts—are grown on the deeper, better-drained and more fertile soils of the region. Fruits and nuts amount to 33 percent of the region’s value of production in 1995. Vegetable crops, mostly processing tomatoes, contributed 16 percent, and livestock and livestock products, an additional 11 percent, of the regional production total.About a third of California’s farmland and 55 percent of its irrigated lands lie in the San Joaquin Valley. Nearly 90 percent of valley cropland is irrigated. The eight counties of the San Joaquin Valley accounted for $12.75 billion of the $22.1 billion total value of California agricultural production reported for 1995 . Unlike the Sacramento Valley, the San Joaquin does not have a single river system that runs through the entire valley. The southern portion of the valley is two lake basins, historically fed by seasonal runoff from the Sierra Nevada Mountains to the east. Early farming depended on private and cooperative development of water supplies from Sierra rivers to irrigate alluvial lands on the east side of the valley, and on the reclamation of the Tulare and Buena Vista Lake Basins in the south valley bringing more acreage into agricultural production. In the post-World War II period, federal and state surface water development brought additional water supplies to the most southern area and to the entire western San Joaquin Valley, which had formerly depended on limited and often poor quality groundwater. Because much of the valley is either of a desert or steppe climatic type, irrigation is the major factor that has made the San Joaquin the most extensive and productive of the agricultural regions of California.