Land and Soil – United States
Maximizing productivity – for today and the future
U.S. cotton growers pride themselves on being good stewards — of their businesses and the land on which they live and work. Stewardship encompasses every action they take to keep the land increasingly productive today and far into the future.
Due to technological advances in production and best management practices, U.S. cotton yields have doubled over the last 40 years, even as less land is planted.
Producing 1 pound of cotton lint requires 30% less land now than it did in 1980, according to Field to Market’s 2021 National Indicators Report.
A huge factor in this improvement is cotton soil conservation. Soil is agriculture’s most fundamental resource, and modern production practices focus on limiting erosion while increasing soil health. The outcomes include increased yield, reduced production costs and a better long-term outlook for the farm’s productivity.
Initial widespread adoption of soil conservation practices helped create drastic improvements in land use efficiency and soil erosion. These improvements have slowed over the past two decades, not only as adoption of soil conservation practices has slowed down, but due to changes in both economics and climate. The U.S. cotton industry is researching how to continue driving improvements in soil health and conservation as well as how to overcome the barriers to continued improvement in land use efficiency.
Prioritizing soil conservation and health
Soil creation is a long-term process: it takes more than a century to create an inch of topsoil from parent material. And yet soil can be carried away incredibly easily by wind and rain. Bare soil erodes more quickly and significantly than planted soil, where roots help hold it in place. Unhealthy soil, which contains minimal organic matter and has poor soil structure, is also likely to erode more than healthy soil.
As the 2021 National Indicators Report demonstrates, soil erosion trends for cotton clearly improved between 1980 and 2000 – which parallels the rapid adoption of many of the high-impact practices noted above. Since then, soil loss improvement has continued at a slower rate, decreasing roughly 14% between 2015 and 2020 according to the 2016 and 2021 National Indicator Reports. The industry has committed to a 10-year goal of reducing soil loss by 50% compared to 2015.
Soil health practices and benefits
To conserve soil, U.S. cotton growers use a variety of farming techniques that reduce erosion and promote healthy soils. High-impact practices that accomplish both outcomes include conservation tillage, and cover crops. Crop rotation is another common practice in which farmers grow different crops in a sequence on the same land to recycle nutrients in the soil as well as mitigate soil pests.
When growers improve cotton soil health, reduced erosion is an important benefit, but far from the only one. Healthy soil improves a crop’s chances for a higher yield, helps reduce plant stress during short-term drought or pest attacks, and reduces fertilizer inputs. Increasing soil carbon, often referred to as a form of regenerative agriculture, is also seen by many organizations as a key strategy to reducing atmospheric greenhouse gases (GHGs) that contribute to climate change.
Soil carbon is an important indicator of soil health, and the U.S. cotton industry is committed to increasing soil carbon by 30% over the span of ten years.
Practices, progress and research
The U.S. cotton industry is supporting various research projects to improve understanding of soil health, best practices and how to advance grower adoption. Leading organizations like Cotton Inc. and the Soil Health Institute are collaborating together and with agricultural companies on research and outreach efforts. Much of the applied research is directly transferable to farmers and practitioners, and Cotton Inc. supports outreach efforts via the scientists, grower meetings and detailed grower resources like Cotton Cultivated.
To control weeds and diseases, producers traditionally incorporated all crop residues and weeds into the soil surface prior to planting, and then continued to till the soil while the crop was growing. While tilling does control weeds, it also destroys soil structure, making it the soil much more vulnerable to erosion by wind and rain. This also increases water losses from evaporation and decreases the soil’s long-term water infiltration capabilities.
Growers who use conservation tillage reduce the number of times they plow the soil, which preserves crop residue on the surface of the fields. No-till is a form of conservation tillage in which the grower doesn’t plow the fields. Both practices reduce erosion and increase organic matter in the soil, which then helps increase soil carbon accumulation rates. In addition, reducing tillage significantly reduces fuel use and its associated cost to growers.
Two-thirds of U.S. cotton growers report using some form of conservation tillage1.
Cotton growers widely adopted sustainable tillage practices between 1990 and 20102; since then, the overall percentage of growers using these practices has remained steady, although more growers report switching from conservation to no-till3.
As the 2021 National Indicators Report states, research into new technologies as well as social science and community support/outreach will be equally critical for driving adoption of sustainable tillage practices across the remainder of cotton acreage – and thus driving ongoing improvements in soil conservation.
Widespread adoption of conservation tillage practices has resulted in a 44% reduction in soil loss per pound of cotton produced on U.S. cotton acreage over the past 30 years — Field to Market, 2016.
Studying the barriers to adoption
Conservation tillage and no-till are possible in today’s cotton production system thanks to seed treatment fungicides, herbicides and herbicide-tolerant cotton that enable growers to control diseases and weeds without tilling.
One major challenge to further progress, then, is the occurrence of herbicide-resistant weeds. A rise in the incidence of these weeds has limited growers’ herbicide options. To combat herbicide-resistant weeds, growers may need to integrate tillage back into their weed management program, even though increased tillage negates many benefits of soil health practices.
The U.S. cotton industry is supporting a variety of research and outreach projects focused on managing – and suppressing – herbicide-resistant weeds in the short and long terms through integrated weed management (IWM). Cotton Inc., for example, is working with several companies to identify and bring to market non-tillage weed management options that work by using heat, laser, abrasives and more precise tillage.
Source: USDA ERS
Over the past decade, the U.S. cotton industry has made a concerted, national effort to increase the use of cover crops for soil health and conservation purposes. Now, the industry continues to support and partner with nonprofit and academic organizations that are researching and promoting this practice. Recently, research has focused on evaluating cover crops for four major benefits:
- Improved soil health
- Reduced soil erosion
- Improved stand preservation (in other words, protecting young cotton plants from sources of physical damage like blowing sand or dust)
- Increased weed suppression
Cover crops reduce soil loss in several ways. Their roots hold the soil in place, even during winter when cotton is not grown. Their above-ground mass protects the soil from wind and rain while the cover crops are growing, and once they have died, the stalks and leaves are left on the soil surface. The organic matter eventually degrades into the soil, where it contributes to soil carbon accumulation and nutrient cycling.
Annual cover crops, like cereal rye and crimson clover, have traditionally been adopted by cotton growers. Annual cover crops are grown from harvest till planting; the dead stalks and leaves are then left on the soil surface like a mulch after planting to protect the soil, decrease water evaporation and decrease weed emergence. Research projects are continuously running to study the positive impacts of these cover crops on soil health and, ultimately, cotton yield. The ongoing University of Arkansas Cotton Research Verification Program (CRVP) aims to demonstrate the profitability of recommended production practices, including no-till and cover crops, and one 2020 study in this program showed that the combination of no-till with cover crops resulted in 70% less soil erosion and a 1.6% increase in lint yield4. A six-year project at the USDA-ARS Soil Dynamics Lab in Alabama has examined agronomic and economic benefits of cover crops to better understand how to “improve soil quality, conserve natural resources, and increase production efficiency … while reducing risk for producers5.”
As an alternative to annual cover crops, perennial covers (“living mulches”) grow alongside the cotton. Recent research from the University of Georgia has evaluated both annual and perennial cover crops, and the latter show considerable promise for improving soil health and suppressing weeds. The research project was designed to quantify the benefits to cotton production from annual cover crop and living mulch systems compared to conventional management with no cover crop. Researchers have been collecting data on:
- Cotton productivity
- Weed suppression and field renovation
- Soil carbon sequestration, health, nutrient content and hydrology6
Going forward, research will help growers better understand how to balance these living mulch benefits with its need for water and nutrients.
Government’s role in soil conservation
Thanks to benefits like improved crop resilience and efficient use of inputs, growers have strong environmental and economic incentives for maintaining their soil. In addition, the United States expects growers to preserve soil quality and requires crop producers to submit Conservation Compliance Plans to the U.S. Government for approval before they can participate in federal crop programs.
For assistance with soil conservation practices, cotton growers can turn to the National Resource Conservation Service (NRCS). This branch of the U.S. Department of Agriculture develops conservation farming techniques and encourages practices that help preserve the nation’s soil resources. NRCS programs like the Environmental Quality Incentives Payment (EQIP) and Conservation Stewardship Program (CSP) also provide payments to help farmers transition to cover crops7.
The importance of cotton land use efficiency
Land is a precious limited resource. Maximizing the productivity of agricultural lands while minimizing the environmental impact is crucial for feeding, clothing and caring for the world’s expanding population. Cotton is already a model plant, occupying less than 1% of the world’s agricultural lands in 20168 while supplying so much of the world’s textile fiber as well as cottonseed, a source of nutritious cooking oil and protein-rich animal feeds.
U.S. farmers and researchers have long been leaders in finding new ways to increase cotton land use efficiency: requiring smaller areas of land to produce the same or larger yield. Land use efficiency is used as a standard sustainability indicator because it allows the industry to take a broad look at how well U.S. cotton is using available resources. Specifically, it is also one of the ten-year U.S. cotton industry goals: improve land use efficiency by 13%.
Everything the industry does to improve soil conservation and health, as well as water efficiency, sustainable pest management and greenhouse gas emissions influences how efficiently land is used. These practices, for example, benefit growers and the environment in multiple ways, including yield improvements:
- Increasing cotton fiber yields through better varieties and appropriate grower management
- Reducing the amount of water per pound of cotton, especially with highly uniform water delivery systems
- Improving soil health through crop rotation, no-till practices and the planting of cover crops
- Implementing improved irrigation scheduling tools (e.g., computer programs and sensors)
Research into these areas seems most promising for learning how to continue increasing yields, even while decreasing the amount of land required:
- Expanding soil health knowledge and driving increased adoption of soil health practices
- Applying geospatial technologies and predictive digital technology
- Preserving low insect-, weed-, and disease-related yield loss
- Increasing adoption of precision agriculture techniques, including in-field sensors to optimize irrigation or fertilizer use
- Advancing CRISPR genome editing in cotton9 and improving plant breeding
- Improving crop resilience to extreme weather and climate change
Measuring cotton land use efficiency
Land use efficiency is an indicator that demonstrates the relationship between the acreage and the yield. It can be measured in several ways, and each way provides a slightly different picture of how cotton is progressing.
Field to Market measures it in terms of acres planted per 1 pound of cotton lint. Their 2021 National Indicators Report shows that cotton’s land use improved in efficiency most markedly in the 1980s, and again in the latter half of the 1990s and early 2000s. The report also shows that cotton’s land use efficiency has started to decrease in recent years.
Increasingly frequent extreme temperatures, droughts, flooding and other weather events in the past decade have led more growers to make the difficult decision to “abandon” planted acres. In other words, they determine the damage is too great for the cotton on those acres to recover without costly intervention, and so they cease to manage those acres for the season. The large amount of abandoned acres in some years has decreased U.S. cotton’s overall land use efficiency when it is measured using planted acres, rather than harvested acres.
When measuring land use efficiency using harvested acres, the picture looks different: cotton’s land use efficiency improves per acre.
2021 yield: 8.78 billion pounds of lint produced
2021 land use efficiency:
- Planted acres/1 lb. lint: 0.00128
- Harvested acres/1 lb. lint: 0.0011310
The U.S. industry is aware that different methods of measuring cotton land use efficiency provide different insights and is taking these insights into consideration while pursuing a unified goal: increase land use efficiency for the good of growers and the environment.
Looking ahead in soil health and land use
The U.S. cotton industry has achieved decades of progress in cotton yields, land use and soil health. U.S. growers, researchers and industry organizations across the country are taking necessary steps to ensure that improvement continues, despite the challenges. Soil health and land use are simply too important and influence too many other environmental and economic factors to stop pushing for progress.
1Daystar, J. S., Barnes, E., Hake, K., Kurtz, R. (2017). Sustainability Trends and Natural Resource Use in U.S. Cotton Production. BioResources 12(1), 362-392.
22021 National Indicators Report.
3Daystar et al. (2017).
4 Arkansas Agricultural Experiment Station. (2021). Summaries of Arkansas Cotton Research 2020. Ed. by Fred Bourland. Accessed June 7, 2022
5 Price, A., et. al. (2022). “Conservation systems to improve production efficiency, reduce risk and promote sustainability.” Retrieved June 23, 2022
6 Lameiras, Maria M. (Jan. 6, 2022). UGA researchers evaluate the benefits of cover crops, living mulches in Georgia cotton. CAES Newswire. Accessed May 13, 2022.
7 Myers, R., Tellatin, S., Weber, A. (2019). When Incentive Payments Are Received for Cover Crop Use. Sustainable Agricutlure Research and Education. Accessed June 7, 2022.
8 Cotton Inc. (2020.) “Land use and cotton production.” Accessed June 7, 2022
9 It has been demonstrated already in cotton; see Plant Molecular Biology 2017 DOI 10.1007/s11103-017-0599-3; Scientific Reports 2017 DOI: 10.1038/srep43902 for more information.
10 National Agricultural Statistics Service (NASS), Agricultural Statistics Board, United States Department
of Agriculture (USDA). (Dec. 9, 2021). Crop Production. Accessed June 7, 2022.