重新思考土壤路线图（英文版）.pdf

Executive Summary / reThink Soil / 1 A roadmap for collective action to secure the conservation and economic benefits of healthy soils A Roadmap to U.S. Soil Health reThink Soil 2 / reThink Soil / Executive Summary Executive Summary / reThink Soil / 1 reThink Soil: A Roadmap for U.S. Soil Health Soil health is inextricably linked to broader conservation goals Improving soil health on U.S. agricultural land holds the potential for achieving meaningful conservation and economic benefits, as well as mitigating the growing threat of climate change. Healthy soil is the cornerstone of life on earth, facili- tating ecosystem biodiversity, ample food production, effective water filtration and storage, and carbon sequestration. Advancements in agricultural technology throughout the past century have allowed farmers to feed a population that has grown from less than 2 billion people to more than 7 billion today. Over the same time period, however, soil managed for agricultural purposes in the U.S. has degraded, losing as much as 60% of its original organic carbon content. 1The deg- radation of soils has undermined the productivity of farmers and the resilience of croplands while leading to significant direct and indirect environmental impacts annually on a national level: 346 million metric tons of greenhouse gas emissions 2 4.4 billion pounds of nutrient loss to the environment 3 996 million metric tons of soil erosion 4 48.4 million acre-feet of water used for irrigation 5 Drawing upon respected analyses in soil health literature, The Nature Conservancy estimates the annual societal and en- vironmental costs of the status quo are up to $85.1 billion annually through unintended effects on human health, property, energy, endangered species, loss of biodiversity, eutrophication, contamination, agricultural productivity, and resilience. As global food demand grows, U.S. agriculture needs to be competitively positioned to increase production to meet both domestic and international food requirements. Managing for soil health serves as a nexus for achieving increased produc- tion while reducing the societal and environmental impacts of the current U.S. row crop production system. Improving soil health can yield significant benefits The U.S. Department of Agricultures (USDA) Natural Resources Conservation Service (NRCS) defines soil health as “the continued capacity of the soil to function as a vital living ecosystem that sustains plants, animals, and humans.” The concept of adaptive management is inherent in this well-accepted definition. Adaptive management for soil health means minimizing soil disturbance while optimizing plant diversity, allowing more continuous plant and residue covers to create vital, living ecosystems in the soil. In turn, the soil nurtures a complex web of microbes with the healthiest soils often being those with the greatest diversity and abundance of life. Healthy soil more efficiently stores and recycles carbon, water, and nutrients such as nitrogen and phosphorous. The full version of this abridged paper (available at nature/soil) presents The Nature Conservancys vision for soil health in the U.S., with the goal of a majority of farms managed for soil health by 2025, and a proposed roadmap for collective action amongst key stakeholders. The full version includes a situation analysis, estimation of economic and conservation benefits of soil health, citations to literature used in writing the paper, and additional soil health resources. We need healthy soil Its a modern imperative for long-term agricultural production which is growing, as is the global population. Cover image: Nick Hall; Left image: The Nature Conservancy (Ken Geiger)2 / reThink Soil / Executive Summary Executive Summary / reThink Soil / 3 At the farm level, the benefits of improved soil health include higher rates of productivity and profitability over the long term, as well as reputational value for farmers who put conservation at the center of their management approach. At the societal level, the benefits of boosting soil health are even more profound, including improved water quality, filtration, and storage; richer biodiversity; and reduced greenhouse gas emissions, mitigating the impacts of climate change. In order to estimate the scale of benefits attributable to changes in soil health, the Conservancy chose three management practicesreduced tillage, cover cropping, and crop rotationsto serve as proxies for the adaptive soil health systems, which will vary geographically. Reduced tillage decreases disturbance of the soil, thereby improving the soils ability to retain nutrients and sequester carbon dioxide from the atmosphere. Cover cropping between cash crop seasons is a heritage practice that maximizes the time each year that living roots are building soil nutrients and keeping the surface protected. Diverse crop rotations help build nutrients, limit erosion, and foster soil carbon sequestration. While these three practices do not represent the full spectrum of soil health solutions available, they serve as valuable measurement proxies because of the extensive, validated research on the conservation and economic benefits of each. Estimated benefits based on minimum, average, and maximum potential impacts of cover crops, conservation tillage, and increased rotation practices Economic benefits ($M) of increased adoption by 1% of U.S. corn-soy-wheat acres Value of soil Healthy soils can deliver tangible economic and environmental benefits for farmers, businesses and communities for generations to come. Rafael Araujo Soil health as a scalable conservation opportunity The mission of The Nature Conservancy is to conserve the land and water upon which all life depends. Over the past 65 years, the Conservancy has protected millions of threatened lands, waters, and species. Y et the vision of the organization is a world where people and nature thrive together. T o achieve this vision, we must attend to the major global challenges facing humanity and support the solutions that can be found in nature. For this purpose, The Nature Conservancy examined the opportunity to deliver scalable conservation gains in the U.S. by focusing on the adoption of soil health management systems across row crop agricultural landscapes. The Conservancy assembled a multidisciplinary team of internal experts, interviewed internal and external stakeholders, developed an analytical approach to estimate the technical benefits, and developed a strategic theory of change consistent with our Conservation by Design 2.0 methodology. While the conservation opportunity is sufficiently large, the barriers to widespread adoption of soil health systems are multiple and persistent. Therefore, more collaborative efforts across capable and committed partners, coupled with greater levels of sustained investment, will be required to make meaningful progress. The Conservancy recommends taking collective action across a “roadmap” of highly coordinated set of strategic inventions toward realizing benefits which accumulate among farmers, communities, and future generations. In doing so, we can “reThink” our opportunities with soil.4 / reThink Soil / Executive Summary Executive Summary / reThink Soil / 5 8. Reward farmers who optimize long-term soil health with lower crop insurance premiums Advocate for federally subsidized crop insurance programs to value the benefits generated from improved soil health profiles through lower insurance premiums LEAD ACTORS: Commodity organizations, agri-food sector, conservation organizations seeking to expand constituency, federal and state governments 2. Develop operational management strategies for adaptively integrating soil health practices and systems Build evidence and understanding among farmers regarding operational strategies locally tailored for integrating multiple soil health practices on a farm, including optimal cover crop programs LEAD ACTORS: Research institutions, extension, conservation districts, NRCS, grower organizations, agricultural retailers, private sector 9. Support policies that enable greater investment in soil health Support state and federal policy improvements focusing on reducing barriers to soil health practice adoption, targeting priority areas for implementation, and comprehensively assess impacts for societal value LEAD ACTORS: State and federal governments, conservation organizations seeking to expand constituency 3. Advance the science of soil health benefits Further quantify the economic costs, benefits and environmental impacts of different management practices on soil health, including organic systems, with consideration for different regions, soil types, and cropping systems LEAD ACTORS: Research institutions, Soil Health Institute 10. Build a more diverse constituency for soil health policy Build a strong and diverse network of supporters for soil health policy, including farmers, landowners, the agri-food sector, community leaders, and societal interest groups LEAD ACTORS: Farmers, landowners, agri-food sector, community leaders, societal interest groups 4. Align incentives between landowners and farmers Cultivate understanding among absentee landowners of soil health benefits for society and land value, encouraging new lease arrangements integrating soil health systems and practices LEAD ACTORS: Landowners, farm management companies, lenders, etc. 5. Leverage technological innovation to overcome operational hurdles Leverage technological innovations, such as sensors, drones, cover crop seeding equipment, precision agriculture software and hardware to advance adoption and continued implementation of soil health systems and practices LEAD ACTORS: Public and private research institutions, agricultural retailers 6. Provide broader access to products and services supporting soil health Develop new business models with agricultural retailers providing broader access to new products and services in order to accelerate the adoption of soil health systems and practices LEAD ACTORS: Agricultural retailers 7. Create market signals in sustainability programs for soil health Develop improved indicators rewarding soil health management outcomes in sustainability assessment programs, aligning the incentives of farmers and society LEAD ACTORS: Field to Market, food companies, agribusinesses, leading sustainability programs and farmers 1. Create cost-effective soil health measurement standards and tools Create accurate, accessible, and standardized methods for rapid measurement of key soil health indicators at a scale that impacts management choices by farmers and landowners LEAD ACTORS: Research institutions, private sector, Soil Health Institute, grower organizations SCIENCE AND RESEARCH Overcome the science and research gap to support expansion of soil health management ECONOMIC Overcome economic obstacles by providing the market systems to secure soil health POLICY Improve the policy environment to advance soil health A Roadmap to U.S. Soil Health reThink Soil iStock6 / reThink Soil / Executive Summary Executive Summary / reThink Soil / 7 The Nature Conservancy estimates that the benefits or “size of the prize” for adopting adaptive soil health management systems in the U.S. are significant. Our base case scenario for estimating benefits suggests that for each 1% of cropland 6adopting an adaptive soil health system, annual economic benefits translate into $226 million of societal value through increased water capacity, reduced erosion and nutrient loss to the environment, and reduced greenhouse gas emission, as well as $37 million of on-farm value through greater productivity. In the most optimistic case, the team estimated soil health solutions could address up to $50 billion in social and environmental impacts annually across the U.S. At the high end estimates, the combined potential impact of increased soil health practices could mitigate environmental impacts by almost $50B annually Estimates of GROSS societal off-farm economic benefits and NET on-farm economic benefits accruing to farmers attribut- able to adoption of the adaptive soil health system. Benefits are listed with the mean estimated value of economic benefits. U.S. Potential Societal Benefits (in $ millions / year) Effect of increased adoption by 1% of U.S. acres of corn- soy-wheat Effect of adoption on 50% of U.S. acres of corn-soy-wheat Effect of adoption on 100% of U.S. acres of corn-soy-wheat GHG emission $29.7 $903 $2,387 Nutrient loss $90.1 $2,951 $7,457 Erosion $75.8 $2,657 $6,447 Water benefits $30.6 $923 $2,453 Total $226 $7,435 $18,744 Off-farm economic benefits (corn, soy corn only (in $ millions / year)$36.7 $1,156 $2,991 Restoring soil health can create net economic benefits for farmers while removing environmental and societal costs associated with intensified agricultural production that will otherwise amass into an unfunded liability to be passed along to future generations. Potential mitigation of environmental impact Significant benefits Healthy soil more efficiently stores and recycles carbon, water, and nutrients such as nitrogen and phosphorous. 2013 Jennifer Davidson/tandemstock for The Nature Conservancy8 / reThink Soil / Executive Summary Executive Summary / reThink Soil / 9 Restoring soil health can create net economic benefits for farmers while removing environmental and societal costs associated with intensified agricultural production that will otherwise amass into an unfunded liability to be passed along to future generations. The Nature Conservancy has a rich history achieving conservation goals for the most important landscapes in the world, and this must include the agricultural landscapes that meet societys critical need for food, fiber, and energy, as well as the people whose livelihoods depend on those lands. The Conservancy views soil health restoration as the primary way to bring economic value to farmers while achieving conservation goals. Yet, this strategy is part of an emerging conservation solution setwhich also includes targeted edge-of-field and in-stream solutions for water quality and more precise nutrient management timed to plant needs. Barriers to achieving soil health are multifaceted A small yet influential segment of farmers, including organic farmers, have catalyzed a movement toward a new array of both innovative and heritage soil health practices that protect and build soils. Despite these efforts, widespread adoption of soil health systems appears unlikely unless the multiple barriers to adoption are systemically identified and addressed. These barriers, which are undeniably complex, cluster arou