SECTION 1: Key Findings

© United Soybean Board

• Improvement in five environmental indicators-Land Use, Energy Use, Greenhouse Gas Emissions, Irrigation Water Use and Soil Erosion-varies by crop and over time. Despite concerted efforts by the value chain and aligned government programs, improvement in environmental outcomes from crop production in the U.S. over the past decade is limited.
• For major commodity crops, soil erosion was significantly reduced from around 1990 through 2005; however, since the early 2000s, soil erosion has largely held steady. This reflects a flat trend for adoption of no-till and reduced-till practices recently and a relatively modest adoption of cover crops to date. Understanding why conservation tillage adoption has plateaued will be key to driving future improvements in soil conservation.
• Overall energy use efficiency from commodity crop production has improved over time; however, several major crops have shown increases in energy use over the past decade, resulting from increased use of fertilizer and crop chemical inputs.
• While greenhouse gas emissions have declined over time when considered on a per yield basis, they have held steady or increased on a per acre basis for several major crops driven by increasing nitrous oxide emissions. Reductions in greenhouse gas emissions per acre have only occurred for crops where nitrogen fertilizer use has declined.
• Overall, soils managed under the cropping systems considered in the Field to Market program have increased soil organic carbon stock throughout the last 25 years, according to a recent USDA report, with the greatest increase in 2005.
• Irrigation water use efficiency experienced significant fluctuations over time in response to weather conditions and shifting production regions, but most crops have improved over time.
• Significant improvement in soil erosion, energy use, and greenhouse gas emissions in the 1990s and early 2000s demonstrates that when new technologies and incentives allow farmers to achieve greater efficiency, they will rapidly adopt new practices.
• Further progress through voluntary conservation efforts requires understanding and creating the enabling conditions that support widespread transition to sustainable practices, including providing farmers with financial incentives, technical assistance, and peer learning opportunities.
• Significant opportunities for U.S. agriculture exist to contribute to climate change mitigation through reduction of greenhouse gas emissions, principally through achieving greater fertilizer use efficiency- which will reduce soil nitrous oxide emissions-and the use of renewable energy as well as energy-efficiency improvements. Additional climate mitigation can be realized through reducing tillage and planting cover crops to increase soil carbon sequestration.
• Assessment of biodiversity and water quality trends highlight multiple environmental benefits from strategic placement of diverse, perennial vegetation, including native grasslands within crop landscapes.
• Overall, these findings extend the trend of plateauing progress since the early 2000s that was noted in the third edition of the report (Field to Market, 2016). While the research to develop new technologies is critical to success, it is increasingly clear that social science research and community support to address the agronomic and financial risk related to changing productions systems is necessary to achieve sustained transformation of the agricultural system.

SECTION 2: ENVIRONMENTAL INDICATORS BY CROP

© USDA NRCS

While the National Indicators Report breaks down the trends for each indicator and crop, there are some common themes that begin to emerge when looking across the full scope of the indicator results.

• Across crops, increases in fertilizer and crop protectant use in the past 10 years emerges as a key contributing factor to the increasing Energy Use and GHG Emissions trends. Efforts to improve on input use efficiency have not yet reached widespread effectiveness.
• Reductions in Greenhouse Gas Emissions per acre have only occurred for crops that are using less nitrogen fertilizer over time.
• Soil erosion improvements were greatest from 1990 to 2005, accounting for most of the gain for all crops. Soil loss uniformly increased or held steady in the 2010s. This may reflect the generally flat recent trend for adoption of no till and reduced till practices and the relatively modest adoption of cover crops to date. Understanding why conservation tillage adoption has plateaued will be key to understanding what is needed to drive greater adoption and future improvements in soil conservation.

As we have noted throughout this study, the trends identified are defined by available national scale data. In some instances, there are potentially important drivers of trends that cannot be incorporated into the analysis due to missing information. We discuss data limitations further in the Methodology section. 

Overall, the indicator findings extend the trend that was noted in the third edition of the report (Field to Market, 2016) of a plateauing of the progress made in the 1990s and early 2000s. While the agricultural industry and research to develop new technologies is critical to success, it is increasingly clear that there are also social science and community level factors that contribute to sustained change. Ongoing work within Field to Market and member organizations is exploring what is necessary to accelerate the transition to sustainable practices including: exploring how social science research can inform effective strategies for sustained conservation practice adoption; considering how to incorporate and leverage innovative financial mechanisms to incentivize adoption; and collaborating across the value chain and full scope of agricultural stakeholders in the United States to identify and implement solutions. We remain committed to exploring all possible pathways towards achieving the goals of continuous improvement in environmental outcomes from agriculture. 

SECTION 3: NATIONAL TRENDS IN ENVIRONMENTAL INDICATORS

© USDA NRCS

In addition to assessing sustainability performance by crop, the National Indicators Report also provides national-level trends on biodiversity, soil carbon and water quality, providing landscape-level analysis on three critical indicators where publicly available data is insufficient to draw conclusions on crop-specific performance. 

 

Biodiversity

No singular measure can provide an adequate understanding of the trend in biodiversity in and near agricultural fields. However, studies show that bird and insect populations in the U.S. have been declining for decades while at the same time native tallgrass prairies have been nearly eliminated. Further, the diversity of crops grown has declined overall, with the exception of the Mississippi Portal region. Together, these results signal an overall negative trend in biodiversity in and around farms. 

Habitat loss continues to be a primary threat to biodiversity, not just in the U.S., but worldwide. The declining numbers of acres set aside in the Conservation Reserve Program over the past 10 years contribute to challenges of efforts to restore habitat and protect biodiversity on farms. With increasing reliance on chemical management with non-selective herbicides, populations of certain pollinator larval host plant, like milkweed, have been significantly reduced. 

Agricultural landscapes across the U.S. have opportunities to support diverse and native species and ecosystems that provide important ecosystem services to humanity. Understanding the trends in both the diversity and abundance of species can help to identify what management practices lead to the greatest risk of further biodiversity loss and also what can be done to prevent loss and transform landscapes to support regeneration of biodiversity in agricultural landscapes. This section has highlighted some of the notable trends and what those imply for the risks to biodiversity associated with agriculture in the U.S. and begun to explore what management practices can reduce risk and support greater abundance and higher biodiversity of species. Biodiversity is a natural resource concern of national and global consequence, but it is inherently local. Farmers, with a deep understanding of their lands, are well positioned to identify both the risks and the best mitigation strategies that align with using the land to produce food, fiber, feed and fuel. 

 

Soil Carbon

Overall, soils actively managed under the cropping systems considered in the Field to Market program have increased soil carbon stock during the last 25 years. The greatest soil carbon gain was observed in 2005 and in later years less carbon gain and some increases in carbon losses is observed. These findings are consistent with the analysis of Soil Conservation in Part 1 of this report, which indicate that reductions in reducing soil erosion have largely plateaued as total acres in reduced and no tillage practices has stayed steady. The adoption of conservation tillage is the most significant factor influencing the soil carbon gains observed here, with additional contributions from manure management and including perennial hay in rotations (USDA, 2021). 

While cover crops are included in the USDA analysis, they do not correspond to a significant increase in soil carbon. This is due to a limitation in the data available for the modeling, which does not include details on cover crop termination practice and, as a result, the models assume termination using tillage (USDA, 2021). Better information is needed from surveys on the methods of termination, such as through herbicide application or mechanical rolling, that do not involve soil disturbance. Under those conditions, cover crops are associated with increasing soil carbon (USDA, 2021). While cover crop acreage is currently relatively small, it is increasing and this detail will become an important consideration for assessing trends in soil carbon over time. 

Other conservation practices that increase soil carbon sequestration on a farm are not included in the USDA analysis. For example, conservation practices that convert small areas of sensitive and low productivity cropland within a crop field to grasslands are also increasingly part of the toolkit available to farmers. These include grassed waterways, buffer strips at the edge of fields and prairie strips, as well as using economic and spatial analysis to identify where land can be taken out of production without negatively impacting the profitability of a farm operation. These practices have multiple environmental benefits, including soil carbon storage, erosion control and creating habitat to support diverse ecosystems. 

Over the past decade there has been increasing awareness of the importance of soil organic carbon for agricultural productivity, soil health and climate mitigation. Public and private sector efforts to improve climate outcomes hold promise to accelerate adoption of agronomic practices that improve soil health and store soil carbon. The development of incentives and market programs for these benefits hold promise to accelerate adoption of agricultural management practices through financial and technical assistance to farmers. Future soil carbon sequestration in croplands will depend both on the adoption of SOC sequestering practices as well as on changes in weather conditions from ongoing climate change. Continuing to track trends over time is important for understanding agriculture's potential to contribute to climate mitigation and meeting domestic and international goals and commitments. 

 

Water Quality

Agricultural lands play a critical role ensuring clean water for society and ecosystems throughout the country. Complex weather factors, and the complexity of the biogeochemical cycling of nutrients and the fate and transport of chemicals in the soil, make it particularly challenging to quantify water quality and to attribute changes to any specific cause. Tracking water quality change is therefore a long-term endeavor. Fortunately, there is ample evidence from research at field and watershed scales that certain agricultural practices retain nutrients and soil in the field and thereby reduce the risk of losing nutrients and chemicals to waterways. 

Research at the plot, field and landscape scales analyzing the effects on water quality of in-field practices like cover crops, reduced tillage and edge-of-field practices including riparian buffers and constructed wetlands demonstrates measurable improvements in nitrogen, phosphorus and sediment losses from farms. Although there has been a steady increase in the number of acres receiving NRCS CSP support for these practices between 2017 (728,607 acres) and 2020 (1,701,880 acres), this still only represents 1% of the total U.S. cropland (897,400,400 acres) (NRCS 2021). For these practices to reduce the negative impacts from agriculture on a watershed scale, they need to be implemented ubiquitously, according to local physical conditions and cropping systems. 

Overall, the trends in water quality for economically important watersheds like the Chesapeake Bay and Gulf of Mexico over the past five years do not suggest improvement. Hypoxia in both areas remains problematic and is closely linked to precipitation patterns that either increase or decrease flow in the tributaries and the amount of nutrients, crop protectants and sediment dissolved within. SECTION 4: SOCIOECONOMIC INDICATORS We continue to explore socioeconomic indicators in Part Three of the report to gain a better understanding of the long-term trends in economic sustainability and social well-being associated with commodity crop production in the United States. 

 

• Farm Financial Health: Measured by the debt-to-asset ratio for general cash grain farms, Farm Financial Health has improved over the period of 1996 to 2015, driven by strength of land value and relatively low farm debt.
• Farm Profitability: Crop-specific Farm Profitability represents the financial returns to a farmer above the variable costs of their operation. No clear national trends can be drawn because substantial variation exists between crops as well as over time due to numerous cost factors and crop price trends.
• Generation of Economic Value: Measured by the contribution of all agriculture to the national gross domestic product, commodity crop production has increased the generation of economic value over the period of 1997 to 2015.
• Worker Safety: Improvements in all measures of the Worker Safety indicator-workplace injury, time lost from work due to illness, and workplace fatalities-improved (decreased) over the period analyzed.
• Labor Productivity: Improvement over time in the Labor Productivity indicator is seen for most crops as a decline in the number of hours per acre and per unit of production; for most crops, this improvement has plateaued in the last five to 10 years.