U.S. agriculture currently faces some steep challenges. Climate change and biodiversity loss represent existential threats to the agricultural status quo. As farmland becomes less functional as a result of increasing stresses from drought, floods, pests, and heatwaves, its regulation by diverse organisms becomes ever more important. A reference to diversification is fundamentally a reference to restoring the ecosystem function of farmland by allowing living organisms to reclaim roles that beginning in the mid-20th century have been assigned largely to synthetic chemicals or machines in conventional farming.
However, as with all social-ecological systems, change in any part of the system necessarily requires or causes change in other parts of the system. Thus, diversification also relates to changing the function of the human elements of the system. That means that not only human choices about management, but also choices about who has the opportunity to manage land become important. The question of how to diversify farm production is closely linked with the question of expanding access to land. Who manages land determines which scientific perspectives, crop choices, traditions, and skills shape the landscape, with profound implications for its ecological sustainability. However, NSAC covers the land access issue elsewhere.
On the eve of the 2023 Farm Bill reauthorization, this post drills down into the potential shape of a diversified U.S. agricultural landscape and the policies that are most closely aligned with incentivizing its creation. It is important to acknowledge that strong solutions will necessarily include reshaping the way in which policy affects historically underserved farmers, as NSAC’s Climate Values Statement lays out. However, this post focuses on those policies most directly shaping on-farm landscape diversity.
The appearance of a diversified farm landscape will vary widely depending upon the wider ecosystem within which it exists and the producer’s choices. So, perhaps most useful is to consider the goals of diversification, and what kinds of systems may contribute to achieving them.
Diversification in practice
Diversification may mean a variety of changes in a farm or ranch system. In cropping systems, it may include increasing structural diversity of the crops themselves, as by having cut and uncut strips of alfalfa. It might mean growing multiple crops from different plant families (intercropping), and/or varieties of the same species together. Including noncrop vegetation alongside crops may further increase genetic diversity in a geographic area, as with prairie strips or field borders and other conservation buffers within or adjacent to crop fields. And diversity may also include the temporal diversity of crop rotations. Some farmers and researchers like those running the Wisconsin Integrated Systems Cropping Trial are developing increasingly sophisticated polyculture with two or more crop species in the same field at the same time.
Greater increases in structural, variety, and species diversity may be created with agroforestry systems, mixing trees and shrubs into annual and perennial grain, legume, and vegetable crops. And by mixing some or all of the above systems across the landscape, the benefits of diversity increase substantially, especially for goals like pest suppression.
And beyond the diversification associated with cropping fields, adding livestock diversity into a system can reduce challenges like pests and diseases while allowing for nutrient cycling from livestock to soil and back to crop or forage species. Diversity within livestock systems, as with having chickens or small ruminants follow cattle in a pasture-based rotation, also provides multiple benefits, including pest suppression.
Suppressing pests and disease
Much of pest management in conventional systems relies on synthetic pesticides, often alongside genetically modifying a single variety for resistance to sprays, in the case of herbicides.
However, diverse systems can carry out similar functions while adding multiple benefits and removing the costly pesticide treadmill, where farmers must always be on the lookout for more chemicals or a new chemical mix in the face of ever-growing and evolving pest populations.
Simple changes in structural diversity, like the alternate cutting of alfalfa mentioned above, can allow pest’s natural enemies to remain nearby, helping to keep pest populations in check. Genetic diversity with a single species can reduce the occurrence of disease like some fungal infestations. Intercropping and strip cropping–in which two or more production crops are grown simultaneously or in relay planting schemes within a field–slow the spread of pests and diseases, can support natural enemies of pests, and mitigate economic losses when one crop fails. Prairie strips or other noncrop strips along fields also offer refugia for beneficial species or, depending on species used, can act as trap crops that lure pests away from a cash crop.
Rotating crops also significantly reduces pests and diseases. Similarly, polycultures and agroforestry systems can reduce outbreaks of pests. Agroforestry systems, for example, increase the presence of birds that are natural enemies of larval pests in some annual crops. Mixed landscapes, by breaking up the kinds of plants to which pests have access, also reduce pest presence, often through greater presence of beneficial species.
Improving production and net returns
Diversity often also increases crop production, quality, or stability of production. For example, research demonstrates that genetic diversity within a single-species monoculture may make yields more stable. Carefully planned crop rotations often increase the yield of the primary crop. When crops are selected carefully and are well matched, intercropping and strip cropping often result in “overyielding” in which total marketable yield is greater (typically by 5-30%, occasionally more) than would be predicted from the yields of each crop grown in monoculture in the same environment. More diversity within pasture polycultures can enhance the nutritional quality, animal health benefits (e.g., micronutrients, parasite-suppressive plant compounds), climate resilience, and sometimes quantity of forages produced. In addition, diversity at the landscape scale, including crop rotations and intensively managed grazing, often allows for overall increases in production and profitability by offering reduced need for synthetic inputs, decreased pest pressure, and more diverse income sources.
Integrating livestock into cropping systems offers potential for increased profitability as well, by further reducing the need for synthetic inputs, and, depending on species mixes chosen, reducing the impacts of pests and diseases as well.
Reducing the impacts of climate change
Increased diversity also buffers the effects of climate change. With rainfall more often coming in heavy, concentrated events, soils that have more water-holding capacity and faster water infiltration will fare better than lower-capacity, less permeable soils, from which much of the downpour runs off overland, carrying precious soil with it. Absorptive, high-capacity soils lose far less soil to erosion and store more moisture to sustain crops through periods of drought.
Some of the most significant gains to soil water infiltration and water holding capacity come with adding perennial plants to a system. That includes agroforestry systems, perennial pasture systems, and perennial grain crops. Perennial vegetation provides soil coverage, protecting soils from the destructive effects of direct raindrop impact during heavy storms, as well as permanent root channels that enhance infiltration. Even in all-annual production systems, practices such as strip cropping, intercropping, and relay planting that combine crops of contrasting seasons and architectures can limit runoff and erosion and improve moisture retention by ensuring that, at no time, is the entire field left uncovered and exposed to the elements.
The addition of agroforestry to an agricultural system can buffer not just variation in precipitation, but also temperature and winds. Greater shade and shelter, carefully planned, can protect against both extreme cold events and extreme heat.
Polycultures generally can also offer some buffering of climate stress, with temporal and/or spatial diversity ensuring that some species thrive even when conditions are extreme.
Drastically reducing erosion and building soil
One of the greatest challenges to farm production, alongside climate change and biodiversity loss, is soil loss. Healthy, biologically rich soils are the foundation of effective crop and livestock production. Not only are soils important for productivity, but they are also key to managing water on the landscape through both droughts and floods. They also have the potential to sequester carbon and to replace synthetic inputs if they are working in concert with the right organisms above and below ground. Diverse above-ground systems and reduced soil disturbance can work together to reduce erosion and even build soil over time. For example, in several USDA ARS Long Term Agroecological Research sites, organic crop rotations that include cover crop, cereal grain, and/or a perennial sod phase have accrued more soil organic carbon and supported more microbial activity and better nutrient cycling efficiency than conventional corn-soy rotations. Long rotations that include several years in pasture alternating with several years in annual crop with winter cover crops have much lower erosion risk than corn-soy or wheat-fallow without cover crops.
Policies to incentivize a diversified food system
Risk management programs
Farm risk management programs actively incentivize fairly homogenous, chemical-dependent conventional systems. Despite natural vulnerabilities to pests, erosion, and particular susceptibility to worsening weather events, subsidized crop insurance, commodity revenue support programs, and disaster assistance artificially shift risk from farmers onto taxpayers to the tune of billions each year. What amounts to structural profit guarantees for conventional farms removes any market incentive which would otherwise exist for these operations to diversify production and markets or otherwise manage risk on-farm. While 20 percent of farms receive more than 75 percent of subsidies, most farms–and certainly most highly diversified farms–are not able to access farm safety net programs at all.
The programs that makeup the federal farm safety net have become wealth entitlement vehicles for the country’s largest and most lucrative conventional farms, highlighting the urgent need to return to a safety net that protects farmers from unexpected losses that accompany farming. It is necessary to introduce reasonable payment limits and means tests on currently unlimited crop insurance subsidies and close loopholes to payment limitations in commodity revenue support programs. This would save dozens of billions of dollars in a Farm Bill cycle where there is “no new funding” which may be used to invest in programs that help farmers diversify and adopt soil health practices. We must also expand access to the safety net for diverse farmers and ranchers. Ultimately, the risk reduction value of diversification should be incorporated into the risk rating methodologies used to determine both crop insurance premiums and eligibility for credit. The Whole Farm Revenue Protection (WFRP) insurance program has taken a step in the right direction, yet even this program needs improvement to realize its full potential to reward and support risk management through crop diversification.
The Agriculture Resilience Act
In addition to better managing farm risk, many of the policies in the Agriculture Resilience Act (ARA) directly address the need to diversify the farming system. Among the most important policies in that regard are those that support advancing pasture-based management, agroforestry, and more comprehensive farm planning across an operation.
Advanced grazing management
Advanced grazing management means more intensive farmer involvement with the day-to-day health of pastures. Methods that move livestock multiple times per week, even on a daily basis, have excellent outcomes for improving pasture plant diversity and health–both of which contribute strongly to improved soil health. In turn, the improvements to soil health create an overall boost in ecosystem health as the soil biota become more diverse and contribute to managing pests within the ecosystem. Rotational grazing can also support carbon sequestration rates up to one ton of carbon per acre annually, provided that the rancher implements best management practices including regionally appropriate and adaptive grazing schedules, stocking rates, and rest periods.
Strengthening the Grazing Lands Conservation Initiative, with its focus on farmer and rancher education on pasture management, is one important policy to support this work, alongside dedicating 50% of livestock spending within the Environmental Quality Incentives Program to advanced grazing practices and prioritizing advanced grazing management throughout the farm bill conservation programs. Further, another key grazing policy within the ARA pilots the Grasslands 30 program within the Conservation Reserve Program (CRP), thus allowing grassland existing the CRP or CRP Grassland Initiative and grassland of prime ecological or habitat significance to enroll in 30 year programs that allow for sustainable grazing. All of these policies help to shift U.S. agriculture toward more diverse landscapes that directly reduce greenhouse gasses and increase agrobiodiversity.
Comprehensive farm conservation assistance
Similarly, comprehensive farm management, as supported and promoted by the Conservation Stewardship Program (CSP), helps farmers to adopt and integrate advanced conservation methods into their farm systems. For example, that means that farmers implementing cover crops can work toward developing permanent cover on their fields–systems that use no-till drills and always plant one crop or cover into the previous crop can improve the health of the agroecosystem and help to sequester substantial carbon. Advancing temporal diversity of fields is one means to improving soil health, reducing erosion, and advancing agrobiodiversity.
The ARA policies shaping CSP include increasing the minimum payment for the program–a change that would effectively support smaller, already-diversified producers at further advancing their means of protecting soil, reducing use of synthetic fertilizers and pesticides, and increasing the presence of diverse species on the landscape. The ARA also creates supplemental payments within CSP for diversified perennial production systems that can go far toward reducing the impacts of climate change and at sequestering carbon. The ARA also specifically ensures that organic and transitioning-to-organic producers receive payments for organic practices under the program. All of the above provide incentives for producers to further diversify their production, with all of the attendant benefits.
Advancing agroforestry and other diversified, perennial systems
Agroforestry is probably among the most powerful means to advance goals of soil health, greenhouse gas mitigation, water quality improvement, and mitigation of climate hazards like drought, floods, and other storm impacts. The ARA offers support for expanding the agroforestry research system that will further develop our understanding of all the benefits agroforestry offers to farming systems, as well as how they can best be implemented to ensure farmers gain economic benefit from diversifying into trees, shrubs, and other perennial crops. The most value is to be gained from mixing multiple crops in space and time, and that includes incorporating perennials throughout existing systems.
The ARA’s support for the agroforestry research program expands the existing agroforestry research centers by adding three more, and expanding their ability to provide technical assistance to farmers and ranchers. It also provides grants for agroforestry demonstration farms.
In addition, the ARA adds perennial, organic, and agroforestry, among others, to the list of expertise offered by the Natural Resources Conservation Service as it provides technical assistance to producers.
Agroforestry systems offer substantial benefits, but still require substantial research support to help farmers integrate them into current systems, and to provide options that respond to the challenge of climate change. The ARA policies offer the needed support for these improvements.
Research policy for diversification
The ARA provides additional key changes that support diversification through research. For example, it strengthens and expands the Sustainable Agriculture Research Education program by creating new resilience centers. These centers would make it possible for farmer-led, collaborative research to develop solutions to the climate and other ecosystem challenges that diversity could do so much to address. Through its farmer-led research programs, it provides substantial opportunities to develop diversification options that farmers will be able to easily assimilate into their work.
Similarly, the Long-term Agroecosystem Research (LTAR) network conducts research that has made substantial strides toward better understanding of the importance of diversity. The ARA would make that network a permanently authorized Farm Bill program. The Climate Hubs, with their role in amalgamation and dissemination of that research to the agricultural community, also receive permanent funding under the ARA. All of these programs are key to developing and implementing diversified systems on the ground.
Summary
Diversifying farm systems is a fundamental element of turning agriculture toward solutions to climate change and biodiversity loss. To meet diversification goals, the 2023 Farm Bill must include policies that improve risk management systems and that bolster incentives and research for diversity–many of which are contained in the Agriculture Resilience Act.