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Irrigation delivery organizations released water from systems for a variety of users, purposes

Thursday, February 18, 2021

According to USDA’s 2019 Survey of Irrigation Organizations, irrigation delivery organizations such as irrigation districts and ditch companies supplied an estimated 41.4 million acre-feet of off-farm water to U.S. farms and ranches in 2019. These organizations also delivered water to other customers: 2.3 million acre-feet to domestic users, 1.5 million acre-feet to industrial users, and 1.5 million acre-feet to other irrigation organizations. In addition, organizations intentionally released water from their systems for other purposes, including 3.1 million acre-feet for downstream users, 1.2 million acre-feet for managed groundwater recharge, and 1.0 million acre-feet to meet environmental requirements. Beyond these intentional deliveries and releases, a total of 10.7 million acre-feet of water left organization systems as conveyance losses, which represents water lost to groundwater seepage or evaporation during transport or storage. This implies an average conveyance loss rate of 16 percent. As the second largest outflow from water delivery systems, reducing conveyance losses is an important focus for water conservation efforts. However, hydrologic systems are complex natural systems, so conveyance losses in many cases provide benefits elsewhere in the environment. For example, conveyance losses may provide unmanaged groundwater recharge or indirect flows into surface water systems that can support wildlife habitat. This chart is based on data found in USDA’s Survey of Irrigation Organizations, updated December 17, 2020.

Irrigation delivery organizations acquired most water from Federal water projects and natural water bodies

Monday, February 8, 2021

USDA’s 2019 Survey of Irrigation Organizations identified 2,543 irrigation organizations that delivered off-farm water directly to U.S. farms and ranches, including irrigation districts, ditch companies, acequias, and similar entities. Water is measured in “acre-feet,” or the amount of water needed to cover one acre of land under a foot of water. Irrigation delivery organizations obtained their water supplies, which totaled more than 70 million acre-feet, from a variety of sources. About 29 million acre-feet came from Federal water projects, which are large water storage and distribution systems built and maintained by the Bureau of Reclamation, the Army Corps of Engineers, and the Bureau of Indian Affairs. Irrigation organizations diverted an additional 22 million acre-feet directly from natural water bodies, such as rivers, streams, lakes, and ponds. The next largest sources of water were State water projects and private or local water projects, which delivered a combined 14 million acre-feet of water to organizations in 2019. Other water sources include water from other reservoirs, often owned by the organizations themselves (2 million acre-feet); water purchased or contracted from other suppliers (2 million acre-feet); groundwater pumped from well fields into water conveyance infrastructure (1 million acre-feet); water obtained directly from municipal and industrial suppliers (0.5 million acre-feet); and water captured from agricultural drainage systems (0.3 million acre-feet). This chart is based on data found in USDA’s Survey of Irrigation Organizations, updated December 17, 2020.

U.S. irrigation organizations performed a variety of water management functions

Friday, January 15, 2021

The 2019 Survey of Irrigation Organizations (SIO), jointly conducted by USDA’s Economic Research Service and National Agricultural Statistics Service, collected information about different types of organizations involved in the local management of water supplies for irrigated farms and ranches. Irrigation organizations directly influence on-farm water use through delivery of irrigation supplies and management of groundwater withdrawals. According to the survey’s data, in 2019, there were an estimated 2,677 irrigation organizations in the 24 States where most U.S. irrigation occurred. About 95 percent of these organizations—such as irrigation districts and ditch companies—had a primary function of delivering water directly to farms, typically through a system of irrigation storage facilities, canals, pipelines, acequias, and ditches. About 27 percent of organizations were involved in at least some aspect of groundwater management as a primary function, with 23 percent of organizations engaging in both water delivery and groundwater management. Groundwater management may include monitoring aquifer conditions, collecting pumping data, charging pumping fees, issuing permits for new wells, or overseeing aquifer recharge efforts. Some irrigation organizations perform secondary functions, such as delivering water to municipal and residential users (14 percent of organizations); managing agricultural water drainage (11 percent); and generating electricity (3 percent). This chart is based on data found in USDA’s Survey of Irrigation Organizations, updated December 17, 2020.

Since 2000, U.S. cotton producers have increasingly used genetically engineered (GE) seeds with stacked traits

Wednesday, December 16, 2020

Genetically engineered (GE) crops are broadly classified as herbicide-tolerant (HT), insect-resistant (Bt), or “stacked” varieties that combine HT and Bt traits. HT crops can tolerate one or more herbicides and provide farmers with a broad variety of options for effective weed control by targeting weeds without damaging crops. Bt crops contain genes from the soil bacterium Bacillus thuringiensis and provide effective control of insect pests, such as the tobacco budworm and pink bollworm. GE varieties of cotton were commercially introduced in the United States in 1995. GE seeds have accounted for the majority of cotton acres since 2000, expanding from 61 percent of acreage that year to 96 percent in 2020. During this time, the share of cotton acres planted with seeds that had the individual HT or Bt traits shrank as growers turned more often to stacked varieties that carried both traits. In 2000, about 26 percent of total cotton acres were HT only, 15 percent were Bt only, and 20 percent used stacked seeds. By 2020, 8 percent of acres were HT only, 5 percent were Bt only, and 83 percent used stacked seeds. This chart appears in the December 2020 Amber Waves article, “Use of Genetically Engineered Cotton Has Shifted Toward Stacked Seed Traits.”

European Union’s Farm to Fork initiative to reduce use of agricultural inputs may increase food prices and further global food insecurity

Thursday, November 12, 2020

Researchers at USDA’s Economic Research Service (ERS) recently evaluated the potential impacts of the European Commission (EC)’s Farm to Fork and Biodiversity Strategies initiative that calls for restrictions in the use of agricultural inputs such as land, antimicrobials, fertilizers, and pesticides in European Union (EU) agricultural production. The proposal pledges to use EC trade policies and other international efforts to promote a vision of sustainability in agriculture, suggesting intentions to extend the reach of the policy beyond the EU. A mandated reduction in these inputs impacts food prices in three ways: production costs could increase as farmers substitute labor for other inputs; production could decrease as a result of fewer inputs being used; and prices on the international market could increase due to tightening of available supplies. Depending on how broadly these measures to reduce the use of agricultural inputs would be adopted globally, U.S. food prices could rise by 1 to 62 percent, and worldwide food prices could grow by 9 to 89 percent. These rising costs could affect consumer budgets and ultimately reduce worldwide gross domestic product (GDP) by $94 billion to $1.1 trillion, and consequentially, increase the number of food-insecure people in the world’s most vulnerable regions by 22 million to 185 million. This chart is drawn from the ERS report, Economic and Food Security Impacts of Agricultural Input Reduction Under the European Union Green Deal’s Farm to Fork and Biodiversity Strategies.

Genetically engineered soybean, cotton, and corn seeds have become widely adopted

Friday, September 25, 2020

Genetically engineered (GE) seeds were commercially introduced in the United States for major field crops in 1996, with adoption rates increasing rapidly in the years that followed. Currently, more than 90 percent of U.S. corn, upland cotton, and soybeans are produced using GE varieties. Most of these GE seeds are herbicide tolerant (HT), insect resistant (Bt), or both (stacked). The share of U.S. soybean acres planted with HT seeds rose from 7 percent in 1996 to 68 percent in 2001, before plateauing at 94 percent in 2014. Bt soybeans are not yet commercially available. HT cotton acreage expanded from approximately 10 percent in 1997 to a high of 95 percent in 2019. Adoption rates for HT corn grew relatively slowly at first, but then plateaued at 89 percent in 2014. Meanwhile, the share of Bt corn acreage grew from approximately 8 percent in 1997 to 82 percent in 2020. Increases in adoption rates for Bt corn may be due to the commercial introduction of new varieties resistant to the corn rootworm and the corn earworm. Bt cotton acreage also expanded, from 15 percent of U.S. cotton acreage in 1997 to 88 percent in 2020. This chart appears in the Economic Research Service data product, Adoption of Genetically Engineered Crops in the U.S., updated July 2020.

Most conservation practices in USDA’s Environmental Quality Incentives Program are part of multi-practice contracts

Monday, April 13, 2020

Under USDA’s Environmental Quality Incentives Program (EQIP), farmers and ranchers voluntarily agree to implement specific conservation practices in exchange for technical and financial assistance. To study how well program incentives line up with participant motivations, ERS researchers collected practice status information about four years after the EQIP contracts were originally signed. Overall, most EQIP contracts were completed as planned—about 80 percent of conservation practices signed in 2010 were completed as originally specified by 2014. For the 20 percent of practices that were dropped, only about 40 percent occurred with the entire contract cancelled or terminated. Some EQIP contracts are simple (single conservation practice), but most contracts are complex (multiple practices). Simple contracts represented 5 percent of all practices on contracts signed in 2010, and slightly less than 5 percent of all conservation practices dropped by 2014. Complex contracts that were entirely cancelled or terminated contained 35 percent of all of the practices dropped (by 2014) even though those same contracts only represent 5 percent of all practices (completed and dropped by 2014). However, the largest share of dropped practices (almost 60 percent) occurred on complex contracts where at least one of the originally planned practices was completed as planned. This suggests that farmers’ incentives to complete conservation practices can vary within a contract. This chart uses data from the Economic Research Service (ERS) report, Working Lands Conservation Contract Modifications: Patterns in Dropped Practices, released March 2019. The topic is also discussed in the ERS Amber Waves article, “Partially Completed Conservation Contracts Reveal On-Farm Practice Incentives.”

Price of fertilizer and prices received for crops have been relatively volatile since 2002

Wednesday, February 26, 2020

Fertilizers provide nutrients (such as nitrogen) essential in the production of crops. The amount of fertilizer farmers use can be affected by changes in the price of the fertilizer, variation in production practice (such as the type of tillage employed and crop mix), and the price received for the crops. From 1960 through 2002, both fertilizer prices paid and crop prices received by farmers increased in tandem at a fairly modest rate. Between 2002 and 2008, annual fertilizer prices paid by farmers increased rapidly (generally much faster than increases in crop prices received by farmers) and became more volatile. Fertilizer price increases through 2008 were largely driven by high energy prices and the record costs of natural gas (a basic input to produce nitrogen). In response to record fertilizer prices in 2008, farmers reduced their use of fertilizers, contributing to a decline of 18 percent in fertilizer prices through 2010. Fertilizer prices recovered somewhat through 2012—driven by strong domestic demand for plant nutrients due to high crop prices, and limited domestic production capacity—before declining again. Since June 2017, fertilizer prices have trended upwards, along with crop prices received. Using an index that sets 2011 price levels to 100, farmers paid 66.7 for fertilizer and received 86.8 for their crops in 2018. In other words, farmers paid less for fertilizer and received less money for their crops in 2018 than they did in 2011. This chart appears in the USDA, Economic Research Service data product, Fertilizer Use and Price, updated October 2019.

Soybean farmers in States with more glyphosate-tolerant weed species appeared more likely to use dicamba-tolerant seeds

Wednesday, October 2, 2019

Left untreated, severe weed infestations can reduce soybean yields by more than 50 percent. Glyphosate is a broad-spectrum herbicide that kills most broad-leaf weeds and grasses. Genetically engineered glyphosate-tolerant soybeans were commercialized in 1996, and in the years that followed, the share of acres planted with glyphosate-tolerant soybeans and treated with glyphosate increased rapidly. By 2006, almost 9 out of every 10 acres were planted with glyphosate-tolerant seeds. As glyphosate-tolerant seed use became more common, an increasing number of soybean farmers started using glyphosate as their sole source of weed control. By 2018, glyphosate-tolerant weeds were identified in the majority of soybean-producing States and were particularly problematic in States located southwest of the Corn Belt, such as Mississippi, Kansas, Tennessee, Arkansas, and Missouri. Herbicides other than glyphosate, such as dicamba, can help control glyphosate-tolerant weeds. In 2018, about 43 percent of U.S. soybean acreage was planted with dicamba-tolerant seeds. The States with the most dicamba-tolerant seed use were Mississippi (79 percent of soybean acreage), Tennessee (71 percent), and Kansas (69 percent). Notably, there appears to be more dicamba-tolerant seed use in the States with the most glyphosate-tolerant weeds. This chart appears in the October 2019 Amber Waves feature, “The Use of Genetically Engineered Dicamba-Tolerant Soybean Seeds Has Increased Quickly, Benefiting Adopters but Damaging Crops in Some Fields.”

ICYMI... U.S. farmers adopting drought-tolerant corn about as quickly as they first adopted herbicide-tolerant and insect-tolerant varieties

Tuesday, August 27, 2019

Droughts are among the most frequent causes of crop yield losses, failures, and subsequent crop revenue losses across the world. Genetically engineered (GE) and non-GE drought tolerance became broadly available in corn varieties between 2011 and 2013. By 2016, 22 percent of total U.S. corn acreage was planted with DT varieties. To better understand this growth rate, ERS researchers compared it to the adoption of GE herbicide-tolerant (HT) and insect-resistant (Bt) corn. Between 1996 and 2000, HT corn acreage increased from 3 to 7 percent of total U.S. corn acreage, while Bt corn acreage increased from just over 1 percent to 19 percent. By 2012, nearly 75 percent of U.S. corn acres were planted to varieties with at least one GE trait. In 2016, 91 percent of DT corn fields also had HT or Bt traits. Some evidence suggests that these three traits are complementary. For example, a corn crop will generally be less vulnerable to drought if it is not competing with weeds for water, and if its roots and leaves are not damaged by insect pests. This chart appears in the January 2019 ERS report, Development, Adoption, and Management of Drought-Tolerant Corn in the United States. This Chart of Note was originally published March 21, 2019.

ICYMI... Use of herbicide-tolerant seeds increased quickly following their commercialization, but plateaued in recent years

Tuesday, August 20, 2019

A genetically engineered (GE) plant has had DNA inserted into its genome using laboratory techniques. The first GE herbicide-tolerant (HT) crops, which can survive applications of herbicides like glyphosate or glufosinate that kill most other plants, were created by inserting genes from soil bacteria. Generally, the use of HT corn, cotton, and soybeans in the United States increased quickly following their commercialization in 1996. HT soybean use increased most rapidly, largely because weed resistance to herbicides called ALS inhibitors had developed in the 1980s. By comparison, HT corn use increased relatively slowly, perhaps because corn farmers could use the herbicide atrazine, an effective alternative to glyphosate that could not be applied to soybeans or cotton. The percent of acreage planted with HT corn, cotton, and soybeans has plateaued in recent years, partly because adoption rates for these seeds is already quite high and because weed resistance to glyphosate has continued to develop and spread. As the problems posed by glyphosate-resistant weeds intensify, crop varieties with new HT traits are being developed. For example, a new HT variety of soybeans that is tolerant of herbicides called HPPD inhibitors will be available to U.S. growers in 2019. This chart appears in the December 2018 Amber Waves data feature, “Trends in the Adoption of Genetically Engineered Corn, Cotton, and Soybeans.” This Chart of Note was originally published February 28, 2019.

Drought-tolerant corn varieties often planted on non-irrigated fields

Monday, July 29, 2019

Droughts are among the most frequent causes of crop yield losses, failures, and subsequent crop revenue losses across the world. Farmers with access to ample sources of irrigation water can, at least partially, mitigate drought stress. Farmers can also plant drought-tolerant (DT) crop varieties—in 2016, DT varieties made up 22 percent of total U.S. corn acreage. DT traits improve the plant’s ability to take water up from soils and convert water into grain under a range of drought conditions. The use of irrigation does not preclude the use of DT corn. For example, nearly 31 percent of Nebraska’s irrigated fields were planted with DT varieties. Farmers’ decisions to irrigate their DT corn fields are influenced by many factors, including the extent of soil moisture deficits (if any), amount and timing of rainfall throughout the growing season, and irrigation expenses. However, most of the main U.S. corn producing States generally had higher levels of DT use on dryland fields. For example, 60 percent of non-irrigated fields in Nebraska were planted with DT varieties. This chart appears in the January 2019 ERS report, Development, Adoption, and Management of Drought-Tolerant Corn in the United States. Also see the article “Drought-Tolerant Corn in the United States: Research, Commercialization, and Related Crop Production Practices” from the March 2019 edition of ERS’s Amber Waves magazine.

Increased compliance enforcement would result in greater reductions in excess nitrogen applications

Friday, July 26, 2019

Excess nitrogen runoff from agriculture into the northern Gulf of Mexico is a major contributor to zones of reduced oxygen that pose seasonal dangers to aquatic life and fishing stocks. ERS has studied potential regulatory tools that could provide incentives to adopt nutrient-reducing management practices, such as requiring conservation compliance to qualify for USDA farm program benefits. ERS researchers explored the scope and effectiveness of a hypothetical “nutrient compliance” policy requiring farmers who receive Federal farm program benefits (including conservation and commodity program payments) to limit excess nitrogen fertilizer applications on land within the Mississippi/Atchafalaya River Basin (MARB). The researchers estimated that 14.4 percent of farms in the MARB, controlling 25.1 percent of cropland, apply nitrogen in excess of crop needs and receive program benefits—but that these farms contribute 88.1 percent of all excess nitrogen applications in the MARB. The analysis suggests that 8.7 percent of MARB farms would be affected by a compliance policy that disallows application of nutrients at levels greater than 40 percent above crop needs. Both the expected compliance benefits to farmers and hence the effectiveness of the nutrient compliance policy are influenced by the chance of being found out-of-compliance through inspection and enforcement. It was found that as enforcement goes down, fewer farms and crop area acres, and less excess nitrogen are affected. For example, assuming 100-percent enforcement, the analysis suggests that 71 percent of affected farms would have an incentive to comply (because program benefits exceed nutrient management costs). With an enforcement rate of 25 percent, by comparison, the share of farms estimated to comply falls to 31 percent of those affected by compliance (or 2.7 percent of all farms in the MARB), and the share of excess nutrients that would be controlled falls to 15.7 percent. This chart appears in the ERS report Reducing Nutrient Losses From Cropland in the Mississippi/Atchafalaya River Basin: Cost Efficiency and Regional Distribution, released September 2018.

Landlords who leased out agricultural land were also more likely to lease out oil and gas rights than operators who owned their land

Tuesday, June 25, 2019

Nationally, 4.3 percent of farmland operators and 4.9 percent of non-operator landlords in 2014 reported receiving oil and gas payments. In counties that produced oil or gas that year, about 10 percent of operators and 13 percent of non-operator landlords reported receiving this income. Not all operators or non-operator landlords own their oil and gas rights, and of those who do, not all of them choose to lease out these rights to energy companies for oil and gas production. Out of those who reported owning oil and gas rights with positive value, non-operator landlords were 21 percentage points more likely than operator landowners to lease their rights to energy firms. Non-operator landlords who lived in the same county as their tenant were more likely to allow energy development to occur than non-operator landlords who lived in a different county. Operator landowners, who live on the property and farm it, may be less likely than non-operator landlords to lease their oil and gas rights because they would experience the costs associated with drilling and oil and gas production—including air pollution, increased truck traffic, and risk of water and soil contamination. This chart appears in the June 2018 ERS report, Ownership of Oil and Gas Rights: Implications for U.S. Farm Income and Wealth.

No-till and conservation tillage practices are more common on fields planted with drought-tolerant corn

Monday, June 10, 2019

Droughts are among the most frequent causes of crop yield losses, failures, and subsequent crop revenue losses across the world. In 2016, 22 percent of total U.S. corn acreage was planted with drought-tolerant (DT) varieties. DT traits improve the plant’s ability to take water up from soils and convert water into plant matter. This creates a natural link between DT corn adoption and use of other water-management practices in corn production, such as conservation tillage and irrigation. Minimal disturbance of soils through conservation tillage makes more water available to the crop by reducing evaporation. No-till management—a conservation practice in which farmers do not disturb soils using tillage operations—was used on 41 percent of DT corn fields in 2016, compared to 28 percent of non-DT corn fields. Overall, conservation tillage (including no-till) was used on 62 percent of DT corn fields and 53 percent of non-DT corn fields that year. The higher adoption rates for DT corn suggest that producers may be using conservation tillage to complement the DT corn’s ability to conserve water. This chart appears in the January 2019 ERS report, Development, Adoption, and Management of Drought-Tolerant Corn in the United States. Also see the article “Drought-Tolerant Corn in the United States: Research, Commercialization, and Related Crop Production Practices” from the March 2019 edition of ERS’s Amber Waves magazine.

Harvested cropland declined by 2 million acres in 2018, coinciding with a rise in crop failure

Friday, June 7, 2019

The ERS Major Land Uses series defines “cropland used for crops” as comprising three types: cropland harvested, crop failure, and cultivated summer fallow. In 2018, cropland harvested declined to 312 million acres—the lowest recorded harvested cropland area since 2013 (311 million acres) and 2 million acres less than in 2017. A 2-million-acre increase in crop failure due to drought conditions in several crop-producing areas contributed to the 2018 decline in cropland harvested. Land used for cultivated summer fallow, which primarily occurs as part of wheat rotations in the semi-arid West, also increased by 1 million acres to 16 million acres, continuing the reversal, which began in 2017, of a long-term decline in this category. The area that was double-cropped (i.e., two or more crops harvested) held constant over the previous year at about 6 million acres. This chart uses historical data from the ERS data product Major Land Uses, recently updated to include new 2018 estimates and revised 2017 estimates.

Use of insect-resistant cotton and corn seeds increased quickly and is now widespread

Monday, May 20, 2019

A genetically engineered (GE) plant has had DNA inserted into its genome using laboratory techniques. Some of the first GE crops were created by inserting genes from the soil bacterium Bacillus thuringiensis (Bt) into corn and cotton plants. Bt creates organic, crystalline insecticides that become concentrated in plant tissues, so these GE crops gained insect resistance. Demand increased quickly for Bt corn and cotton after their commercialization in 1996. Five years later, about 37 percent of cotton acres and 19 percent of corn acres had been planted with Bt seeds. By 2018, Bt adoption had increased to 85 percent of cotton acres and 82 percent of corn acres. Early differences in the adoption rates of these two GE crops may be related to the fact that insect infestations tend to be more severe in warmer climates. Cotton-growing areas are concentrated in the Southeastern United States and the Southern Plains, which tend to be warmer than growing areas in the Midwest, where most U.S. corn production takes place. This chart appears in the December 2018 Amber Waves data feature, “Trends in the Adoption of Genetically Engineered Corn, Cotton, and Soybeans.”

GPS guidance systems are used on about half of planted acres for major crops

Friday, May 17, 2019

Guidance systems use global positioning system (GPS) coordinates to automatically steer farm equipment like combines, tractors, and self-propelled sprayers. This helps reduce operator fatigue and pinpoint precise field locations within a few inches. Freed from steering, operators can access timely coordinates from a screen, monitor other equipment systems more closely, and correct problems more quickly. In addition, guidance systems reduce costs by improving the precision of sprays and the seeding of field crop rows. The ends of rows, in particular, benefit from more accurate application of inputs. Manually reversing farm machinery to return in the opposite direction in adjacent rows on a field can cause overlaps and missed spots for applied inputs. Guidance systems can also help extend working hours for field operations during time-sensitive production periods because guided machinery works well in the floodlit dark. Out of all precision agriculture technologies, guidance systems had the highest adoption rates—used on 67 percent of corn planted acres (in 2016), 57 percent of spring wheat (2009), 53 percent of rice (2013), 49 percent of peanuts (2013), and 45 percent of soybeans (2012). This chart appears in the May 2019 ERS report, Agricultural Resources and Environmental Indicators, 2019.

No-till and strip-till are widely adopted conservation practices, but are often used in rotation with full-width tillage

Thursday, May 2, 2019

Tillage—the mechanical manipulation of the soil—helps to prepare the soil for planting, control weeds, incorporate surface-applied manure or fertilizer, and encourage soil warming for early planting. In recent decades, some farmers have eliminated the use of tillage altogether using “no-till” methods, or limited tillage to narrow strips where row-crops will be planted using “strip-till” methods. No-till and strip-till minimize soil disturbance and keep crop residue on the soil surface to reduce erosion and conserve soil moisture. Recent ERS research shows that many farmers who use no-till or strip-till often alternate these practices with full-width tillage (tilling the entire soil surface). On land where corn was planted in 2016, for example, no-till or strip till was used continuously during 2013–2016 on 18 percent, no-till or strip-till was used alternately with full width tillage on 27 percent, and full-width tillage was used continuously on 55 percent. The exact mix of tillage practices varied across the surveys. One reason farmers alternate tillage practices is because of crop rotation. For example, corn and soybeans are often grown in rotation, but farmers used no-till or strip-till more often for soybeans (about 34 percent in 2012) than for corn (27 percent in 2016). In many cases, farmers use no-till when growing soybeans, but use full-width tillage when growing corn. This chart appears in the ERS report, Tillage Intensity and Conservation Cropping in the United States, released September 2018.

Regional strategies for reducing nitrogen loadings to the Gulf of Mexico differ according to how policy objectives are formulated

Monday, April 22, 2019

Every summer, a “hypoxic zone” forms in the Gulf of Mexico where dissolved oxygen is too low for many aquatic species to survive. This zone is fueled by nutrient (nitrogen and phosphorus) runoff from the Mississippi/Atchafalaya River Basin, a region containing about 70 percent of U.S. cropland. Recent ERS research modeled two scenarios for reducing nitrogen loadings to the Gulf of Mexico by 45 percent. The Gulf Constraint scenario reduces nitrogen loadings at the lowest cost, without consideration of the regional origin of nutrients. The greatest nitrogen reductions would occur in the Lower Mississippi sub-basin (reduced to 72 percent of the baseline amount) and in the Ohio sub-basin (43 percent). Because these regions are relatively close to the Gulf and have relatively high baseline nitrogen discharges per acre (i.e., high potential to reduce discharges by adopting low-cost conservation practices), the estimated cost of reducing nitrogen loadings originating here is generally lower than elsewhere. On the other hand, the Regional Constraints scenario evenly reduces nitrogen loadings by 45 percent from each of the sub-basins. Under the Regional scenario, total edge-of-field nitrogen reductions (and aggregate costs) are projected to rise relative to the Gulf scenario for the Tennessee, Upper Mississippi, Missouri, and Arkansas-White-Red sub-basins and drop for the Lower Mississippi region. This chart appears in the ERS report, Reducing Nutrient Losses From Cropland in the Mississippi/Atchafalaya River Basin: Cost Efficiency and Regional Distribution, released September 2018.

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