Indicators and Soil Conservation Practices for Soil Health and Carbon Sequestration

Soil Health Research
Soil health and soil carbon sequestration results showed few significant differences across land management treatments. Almost all analyses conducted, including aggregate stability, glomalin related proteins, soil respiration, microbial biomass, and PLFA microbial assessments exhibited greater differences across soil types than across land management practices. Similarly, the percentage of organic matter in aggregates larger than 10 mm proved to be significantly different across soil types but not different according to management practices. Permanganate-oxidizable organic matter appears to be the best indicator of differences between no-till and conventional till soils. Preliminary results indicate that levels of permanganate-oxidizable organic matter in aggregates larger that 10mm might be more sensitive to management changes than levels of permanganate-oxidizable organic matter in bulk soil samples. The high clay Blackland (Vertisol) soils consistently showed the greatest aggregate stability, permanganate oxidizable organic matter, and percent of organic carbon in aggregates larger than 10 mm while sandy loam soils consistently exhibited the lowest values for these parameters. Potential reasons for observed differences across management practices may be due to the limited amount of cover cropping implemented on farms analyzed or the limited amount of residue remaining on the soil during the growing season. While several farmers described using cover crops, field observations at the time of sampling indicated limited residue cover. In tangential research conducted by a student associated with an NSF REU program in 2019, soil respiration as measured with a Gasmet DX400 showed significant differences between fields subject to different levels of grazing intensity.
Despite funding for this project having ended, we are continuing to conduct analyses on soils collected using IDC funds from the project. We have also identified additional statistical analysis assistance to examine interactions among various data parameters.

Socio-economic research
Socio-economic research used GIS, US Agricultural Census data, survey and case study information from the literature, detailed interviews with 22 conservation agriculture producers, and interactions with farm support personnel to determine factors affecting farmer decision making regarding the adoption of an integrated combination of conservation agricultural practices or conservation agricultural systems (CAS). In addition, we examined agricultural ecosystem services marketing programs and the potential for the economic benefits provided by these programs to influence farmer adoption of CAS.
Table 1 Example questions from the open-ended telephone interviews conducted with farmers.

Factors stated by interviewed agricultural producers as most important in their decision-making for adopting and maintaining CAS practices included: maintaining soil health and reducing soil erosion, enhancing farm economics by increasing crop diversity or enhancing the sustainability of crop production, the information provided by agricultural educators, and access to government funding such as NRCS cost-sharing. Not surprisingly, soil health and control of soil erosion were the most important CAS decision-making factors for all respondents since these practices are primarily designed to reduce soil erosion, increase soil organic matter, and enhance the biological health of soils. The relative importance of other decision-making factors differed according to farm type. Row crop farmers considered soil health and erosion control and farm economics as the two most important factors affecting their decision to use CAS.

While CAS adoption by farmers has been promoted primarily through educational, technical assistance, and economic support programs, interviewed row crop farmers considered those programs to be only half as important as the environmental and economic impacts provided by CAS. For farmers with a combination of row crop and grazing practices, access to external funding was almost as important as soil health and erosion control. These farmers also had larger farms and tended to be more involved in agricultural policy decision-making than the row crop farmers. Interestingly, farm support personnel perceived both soil health and access to CAS technical and educational assistance to be almost twice as important to farmers’ CAS use decision-making than was reported by farmers.

Farmers who have large enough farms and a dependable labor force could attend conferences and take risks on their land. Subsequently, these farmers became local leaders for conservation agricultural practices. One farmer cooperator attended a cover cropping workshop 10 years ago, was able to test what they learned on their own farm and have since not only have expanded their use of cover crops on their farm. They have also used their custom planting business to make no-till equipment and management knowledge available to local farmers. In addition, they now grow a wide variety of cover crops on their land and sell the seed not only to local farmers but also to the local seed dealer. In this way, they have not only influenced other farmers through their example they have also facilitated the adoption of these practices through the availability of equipment and seed.

The following figures are provided as an uploaded media document
Figure 1. Factors affecting CAS farmer decision making according to farm type or being a farm technical or educational support person

Figure 2. Factors affecting CAS farmer decision making according to the percent of each decision-making factor was supported by each of 3 farm type or being a farm technical or educational support person

Factors identified by these producers as constraining their use of CAS practices included 1) cost of equipment, 2) landlords of rental land who either do not support the use of conservation practices or do not allow farmers to enter into long term leases on the land, 3) variable weather conditions resulting in their not being able to plant cover crops in a timely manner or in spring rains not dependably replenishing soil water taken up cover crops over winter, 4) limited locally-adapted research on these practices, 5) crop insurance policies, and 6) ridicule by neighbors. Land tenure had a relatively minor impact on CAS adoption by farmers since all owned at least some of the land they farmed. It did, however, often affect where CAS was used. Several farmers stated that they used CAS on all their owned land but only on rented land where they had long-term leases. Primary reasons for not using CAS on rental land were requirements by landlords to use conventional practices or short-term leases. Short-term leases constrain CAS use because these practices typically do not provide a return on investment until the third year of use. As organic matter increases in the soil, the ability of the soil to hold water and nutrients increases. However, initially, nutrients are immobilized when crop residues, especially those with high lignin content, are returned to the soil. Some farmers described how they educated landlords by showing them benefits they obtained on land currently managed using CAS. Through this process they sought to obtain landlord permission to implement CAS on the rented land. Competitive renters appear to be aware of the potential economic and environmental advantages from long-term CAS managed land. Several farmers and farm support personnel noted that some people were offering to pay higher rent levels for land that had been managed using CAS. Respondents suspected that these people wanted to take advantage of the higher productivity of this land.

Both farmers and farm support personnel noted that stipulations of agricultural programs constrained their implementation of CAS. Commodity and crop insurance programs limit the use of crop rotations. The U.S. Agriculture Improvement Act of 2018 encourages CAS adoption with specific guidelines that still limit localized adaptation for producers requiring a safety net. More specifically, both cover crops and dual cropping systems are mentioned in the U.S. Agriculture Improvement Act of 2018 with specific guidelines restricting adaptation and flexibility.

Some farmers noted that NRCS cost-share program contracts did not account for farmers’ need to modify farming practices based on weather conditions. For example, heavy autumn rainfall may prohibit farmers from planting cover crops, yet they reported that NRCS programs did not accommodate their need to extend their contracts. Farmers also noted that the environmental and soil health benefits from cover crops allow for more reliable yields during dry years but do not provide a return on the investment during years with more favorable weather conditions. Consequently, several farmers mentioned that they would use cover crops more consistently if processes for obtaining on-going payments for this input were available. Additionally, data documentation by the US Agricultural Census and privacy rules by NRCS limited our ability to assess the implementation of CAS across locations and over time.

The US Agricultural Census provides limited detail on conservation agricultural practices. Only conservation easements, no-till, reduced till, cover crops, alley cropping, and rotational grazing are listed as options on the survey. Census data is combined according to practice but not separated by farms. Thus, it is difficult to determine if CAS practices are being implemented in combination on fewer farms or implemented separately on more farms. Census information also makes it difficult determine whether fewer farmers are implementing practices over longer time periods or more farmers implementing practice for a shorter duration.
While few interviewed farmers stated that ridicule by neighbors constrained their use of CAS, several other farmers noted that fear of ridicule may be affecting practice adoption by current non-CAS users they knew. Typical ridicule aimed at CAS users included, “trashy farmers” and “lazy farmers” due to the perceived lack of management rather than different management practices associated with the use of cover crops and conservation tillage.

Mixed messages from researchers and farm support personnel also constrained farmer adoption of CAS. In the arid areas of western Texas, cover crop use can reduce yields of the commodity crop planted during the following spring. This is because cover crops can take up soil moisture, reducing its availability for the following crop. Climate change has compounded this problem by making rainfall patterns increasingly less predictable. Due to these factors, many AgriLife (cooperative extension) agricultural agents working with farmers in western Texas are reluctant to promote cover crop use. Simultaneously, few AgriLife researchers are conducting research on the selection or breeding of appropriate cover crops for arid areas or on cover crop management practices appropriate for arid areas. Lacking locally adapted practice information, farmers interested in conservation practices may implement tillage practices or plant cover crops that are not appropriate for their location, potentially resulting in practice failure and disillusionment. These conditions occur when private seed or consulting companies advocating cover crop use fill this void, promoting seed mixes that were not developed for specific locations. When farmers experience problems with the growth, soil coverage, or soil health improvement benefits they hoped to gain from these cover crops, they may become disenchanted with cover cropping. Farm support personnel may also use these experiences to further dissuade other farmers from adopting CAS. Conversely, implementation of CAS appears to be related to areas where NRCS, SWCD, and non-profit sustainable agricultural organizations have promoted and prioritized these practices. Individual attitudes are also observed to affect CAS decision making at multiple levels and included statements such as, “It takes belief in self”, “You can’t be afraid to be proven wrong”, and “I have too high of a risk tolerance.”

To determine the economic costs and benefits of CAS, economic and environmental analyses were conducted on 10 CAS farms using the Nutrient Tracking Tool (NTT) and the Farm Economic Model (FEM). These tools account for the ecosystem service value of CAS by calculating factors such as the amount of erosion prevented times the economic value of a ton of topsoil or the amount of water stored in the soil versus the cost associated with applying that much water using irrigation. Using these programs, we created scenarios to compare existing CAS practices to hypothetical conservation agricultural practices. These assessments indicated that combinations of conservation practices enhanced both environmental and economic benefits while implementation of conservation tillage alone resulted in limited or no benefits compared to conventional tillage practices.

Information from farmer interviews, farm support person interactions, and economic data were used to develop systems analysis diagrams. These diagrams are designed to model and assess the impacts of various decision-making processes. These diagrams can also be used in interactions with farmers and farm support personnel to stimulate discussions regarding how decision-making factors interact with one another and regarding differences in the priority given to various decision-making factors. These diagrams can also facilitate dialog between different types of farmers or between farmers and farm support personnel to identify differences in perceptions and needs, which can influence the development of effective programs to enhance CAS adoption.

This figure is included in the media file.

Figure 3. Stock and flow diagram with economic and environmental data interrelated.

Follow-up Work.
As discussed in the soil analyses section above, we intend to continue conducting soil analyses associated with this project with the intent of submitting a paper for publication during summer 2021. We intend to incorporate results from the soil analyses with results from the socio-economic paper to develop a document that addresses the question, "Are soil carbon sequestration payment programs ready for prime-time: soil assessment and socio-economic factors to be considered."