This is a standards based approach, similar to that used by CARB to determine additionality for its current offset protocols, because it sets a single, uniform threshold that must be met for an offset credit to be issued. As long as the average rate of sequestration was accurate, variability between different projects may not matter because the effects of carbon dioxide are largely not localized and so a reduction in one location is just as good as a reduction in another location. Therefore, it may be administratively favorable and just as environmentally effective to calculate the average acreage required to sequester one metric ton of carbon dioxide, then calculate the offset credits to be issued to each offset project based on the acreage being offered for the offset project.Different averages could be calculated for different regions, as soil type varies greatly by region.However, this approach would prove misleading if only plots with lower-than-average sequestration ability engaged in the program. This may occur if soil with higher sequestration ability can also support higher value uses than offset credit generation. If this is the case, the actual soil sequestered under the program would fall below the program’s projected average. This may be indeterminable until the value of the offset credits is established in a market, although prices within a market can always fluctuate and thus not provide the desired stability that alternative uses may provide. Many of these same problems exist in other types of offset projects which have been approved and are currently in use despite their potential accounting inconsistencies.Additionally, by using this standards-based approach, it is very likely that some projects’ carbon sequestration abilities would be lower than the offset program’s average and would be issued more offset credits than would be issued if the projects’ actual carbon sequestration had been measured. This will always be an issue with a standards-based approach, as seen in the Citizens Climate Lobby litigation. Another option is to require a variable amount of acreage per offset credit under an offset project based on how much carbon that particular land is actually estimated to sequester,ebb flow cannabis based on factors that affect a particular land’s sequestration abilities.
This project-by-project option would theoretically give a more accurate estimate of the amount of carbon sequestered by each project, and would thus give managers a better idea of whether a project has actually offset a whole carbon credit. On the other hand, it would also take much more administrative resources and time to administer due to the variability of different land and the measurements required to calculate that variability, which could hinder the offset program’s implementation.Additionally, project-by-project approaches do not always ensure accuracy. The Kyoto Protocol’s Clean Development Mechanism utilized a project-by-project approach to determine additionality, and the results were reportedly rife with error and under- or over-exaggeration when it was convenient. Experience has shown that not even a project-by-project approach will result in perfect results. However, measures can be taken to try to avoid some of the shortcomings of a project-byproject approach. For example, some have suggested replacing opportunities for subjective determinations by the project proponent or host in the project approval or crediting process with objective criteria.This would decrease the opportunities for the project proponent or host to control the outcome of the project’s approval process. Some of the measurements and logistical work could be contracted out to independent third parties at the project proponent’s expense. This practice is used by certification programs, such as the Forest Stewardship Council and the Sustainable Forestry Initiative, in order to save the certification program the resources that would be required to perform the measurements and verifications themselves. Likewise, establishing similar requirements for an offset program would decrease the resources required from CARB and should be acceptable to the project host and proponent as long as the cost is not prohibitive.Whereas a standards-based approach may make sense for determining an offset project’s additionality for the Livestock Protocol due to the protocol’s relative simplicity, its measurability, and the uncommon use of BCSs without financial incentives, these factors are not as clearly present for a potential agricultural soil carbon sequestration offset program. The amount of methane captured by a BCS digester and subsequently destroyed under the Livestock Protocol is measured by a site-specific meter and thus does not present the same difficulties and variables that exist when measuring soil carbon sequestration.The court in Citizens Climate Lobby indicated that a standards-based approach to determine additionality made sense for the Livestock Protocol because the technology was so infrequently used without the financial incentives from the offset protocol.
This line of thinking may not so clearly comport to a possible agricultural soil carbon sequestration offset program due to the existing prevalence of cropland conservation practices.To determine whether this is true of whatever region would be included in the offset protocol, CARB could commission an outside group to analyze current prevalence as they did when formulating the Livestock Protocol.Even if it was discovered that these conservation practices were generally uncommon, as with BCSs, so that additionality could be satisfied by a standards-based approach, the complications associated with other issues may be so complex and variable that a case-by-case measurement process using an ecosystem approach may still be preferable to determine whether the project’s emission reductions are legitimate and lacking in egregious incidental effects.Increased herbicide use as an incidental effect to agricultural soil carbon sequestration offset projects is unique to this type of offset program, but may also be resolved if approached from an ecosystem approach on a case-by-case basis. First, it would need to be determined whether increased herbicide use is actually a threat for the type of land that is participating in the offset program. If so, the effects of herbicide on the local resources and the increased nitrous oxide emissions should be accounted in the project’s approval process. Actively finding and implementing alternatives to herbicide use that make sense for the particular project host would alleviate the effects of increased herbicide use. One option is to replace increased herbicide use due to not ill and conservation till practices with cover crops in combination with other agricultural practices. At least one study claims that cover crops can greatly reduce the need for herbicide.Unfortunately, it seems that it is difficult to naturally replace the benefits of herbicide, as higher crop yields are reported when using herbicide instead of cover crops.Because cover crops and other agricultural practices do not seem to replicate herbicide, it would be unlikely to see a voluntary decrease in herbicide use. If herbicide use was prohibited or limited under a future offset program and no-till or conservation tillage was a major part of the program, it is likely that farmers would not be interested in participating in the program due to the difficulty or impossibility of balancing these two requirements. A better alternative may be to consider implementing a pesticide management program within the agricultural soil carbon sequestration offset project.
The pesticide management program would differ by project, as different projects would likely have different crops with different surrounding environments and site-specific needs. The pesticide management program utilized by the USDA in the Missouri River Basin study observed a decrease in herbicide use when cropland conservation practices were implemented. These practices included prevention, avoidance, monitoring, and suppression strategies to reduce pesticide use. Prevention includes measures such as using seeds and transplants that are free of pests, preventing weeds from reproducing,ebb and flow tables eliminating hosts for pests and disease organisms, and scheduling irrigation to prevent disease development.Avoidance practices include crop rotation to avoid the pest or disease, planting seeds with genetic resistance to pests, choosing crops that will mature and be harvested before pests or disease develops, and not planting in certain parts of the field that are prone to crop failure from pests and disease.Monitoring includes testing to determine crop rotation selection and when suppression activities are required.Suppression includes cultivating and temperature management for weed control, traps and exclusion devices for pest control, biological control by disrupting mating, and more deliberate and informed use of pesticides as a last resort.A well-functioning ecosystem approach to management requires research and consulting with experts from many different disciplines to construct the program and to evaluate each project on a case-by-case basis. This approach requires resources and time above and beyond what would be required for a standards-based approach, the approach currently favored by CARB in its offset protocols. Even once the experts are secured, scientists may remain too narrowly focused on their specific disciplines to do a full or fair assessment for purposes of an ecosystem approach.An ecosystem approach will identify trade offs, which can create a whole separate discussion of priorities and values that may require an extended time frame for considering any program or project evaluated under the ecosystem approach. Additionally, the court in Citizens Climate Lobby identified problems with offset programs that utilize the project-by-project analyses implicated in an ecosystem approach. Aside from being considered expensive and slow, the case-by case analysis utilized under the Kyoto Protocol’s Clean Development Mechanism is often criticized for being inaccurate due to excessively narrow or broad framing of answers to questions that are supposed to determine whether a project is actually additional to a business-as-usual scenario.Despite these drawbacks, following an ecosystem approach when considering an agricultural carbon sequestration offset program and its subsequent projects would be more meaningful and accurate. It would force decision makers to discuss whether a proposed offset program or project would be causing more overall harm than would be caused without the offset program or project and what sort of trade offs would be made.
Currently, harmful externalities of existing agricultural soil carbon sequestration offset programs seem to be ignored in at least some of the programs that implement the offset projects. For example, monitors for one soil carbon sequestration offset project noted that although herbicides are applied without considering the environmental consequences, “these activities are not part of the project under discussion.”An ecosystem approach would ensure that herbicide use and other possibly harmful externalities would be included in discussions concerning the costs and benefits of offset programs and projects. This is especially important for offset programs and projects, which are in theory neutral—trading one ton of carbon in one location for one ton of carbon or carbon equivalent in another location—and helping to implement the environmental purpose of the carbon market. Certain offset programs would garner less support if it was clear that their overall effect on the environment was a net negative. Thus, the ecosystem approach can help decision makers understand and create an agricultural soil carbon sequestration offset program with acceptable trade offs and incidental effects.Naturally occurred and fertilization-induced soil salinity, and low nutrient use efficiency are significant constraints in modern agriculture production . At the cellular level, the extrusion of Na+ ions at the cell plasma membrane and the compartmentation of Na+ into vacuoles are efficient mechanisms to avoid excessive cytosolic Na+ concentration and maintain an adequate cytosolic K+ /Na+ ratio . The plasma membrane electrical potential difference of root cells is usually maintained around 120 mV, while the tonoplast potential is positive and around 20–40 mV . These potentials allow the root to acquire sufficient K+ via high-affinity transporter systems in K+ – limited soils or via low-affinity transporter systems at normal external K+ supplies. The presence of high external Na+ concentrations suppresses the K+ conductance through LATS and competes with K+ uptake through HATS , causing a decrease in intracellular K+ with a concomitant [K+ ]/[Na+ ] imbalance. The plant vacuolar Na+ /H+ antiporters were shown originally to mediate the electroneutral Na+ /H+ exchange, driving the excess cytosolic Na+ into the vacuole . The NHX proteins belong to the large mono-valent cation/proton transporters family, showing three distinct functional clades . In Arabidopsis, in addition to the plasma membrane-located NHX7 and NHX8, also known as SOS , intracellular NHXs sharing high sequence similarity are further divided into type-I and type-II, based on their subcellular location . Type-I NHXs are vacuolar-located, while type-II NHXs are found at endosome, Trans-Golgi Network /Golgi and prevacuolar compartments .