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Most formal drought plans for irrigation organizations specify rules for drought-induced water restrictions

Wednesday, April 6, 2022

Guidelines for implementing drought-induced water restrictions on water deliveries and pumping are the most common component in the formal drought plans of irrigation organizations. In the 2019 Survey of Irrigation Organizations, USDA asked groundwater organizations and water delivery organizations, such as irrigation districts and ditch companies, questions about their formal drought planning. Around one-fifth of all organizations had a formal, written drought plan. Between 69 percent and 73 percent of water delivery organization plans and 80 percent of groundwater organization plans included details about drought-induced water restrictions as a component of their plans. Land fallowing provisions and off-year water storage strategies typically occurred in fewer than 20 percent of plans for most organizations. About one-third of large delivery organization plans included provisions for price increases and water supply augmentation during drought by purchasing additional water. This chart was drawn from the USDA, Economic Research Service report Irrigation Organizations: Drought Planning and Response (EB-33), published January 6, 2022.

Irrigated cropping patterns in the United States have evolved significantly since 1964

Friday, March 25, 2022

Irrigated cropping patterns have shifted significantly in the United States during the past 50 years. In 1964, alfalfa hay and cotton were the most widely irrigated crops, but acreage under those crops has stayed relatively constant since then. Meanwhile, irrigated acres planted in corn for grain and soybeans have increased substantially. In 1964, farmers planted less than 2 million acres of irrigated land in corn for grain. By 2017, irrigated acreage planted in corn grew to more than 12 million acres, making corn for grain the most commonly irrigated crop. Over the same period, irrigated acreage planted in soybeans also increased substantially, from fewer than 1 million acres to nearly 10 million acres. The growth in irrigated corn and soybean acreage reflects, in part, increasing demand for these crops as feedstock sources for bioenergy production and feed for livestock operations, both domestically and abroad. Irrigated corn and soybean expansion also reflects a broader eastward shift in irrigated production acreage over the past five decades. This chart was drawn from the USDA, Economic Research Service report “Trends in U.S. Irrigated Agriculture: Increasing Resilience Under Water Supply Scarcity,” published December 28, 2021.

Use of surface or groundwater for irrigation depends on regional water availability, legal institutions, and infrastructure investments

Monday, March 14, 2022

Surface and groundwater are the two primary water supply sources for irrigated agriculture. Groundwater is pumped from aquifers, while surface water is diverted from natural streams, rivers, and lakes. The predominance of surface versus groundwater use varies regionally. Groundwater is the most common source of water applied for irrigation in the Mississippi Delta, Northern Plains and Southern Plains regions. The prevalence of groundwater-fed irrigated agriculture in the Northern and Southern Plains relates to the regions’ historically abundant groundwater resources. The High Plains Aquifer, the largest aquifer in North America and also known as the Ogallala Aquifer, underlies significant portions of the Plains regions. The Mississippi Delta region also has abundant groundwater resources that are relatively shallow, making groundwater-based irrigation less expensive. Irrigated agriculture relying on surface water is most prevalent in the Mountain and Pacific regions. The extent of surface water use for irrigation in these regions reflects past Federal, State, and local investments in water conveyance and storage infrastructure, as well as characteristics of the regions’ legal institutions which grant water rights based on historical beneficial use rather than ownership of land along streams and rivers. This chart was drawn from the USDA, Economic Research Service report “Trends in U.S. Irrigated Agriculture: Increasing Resilience Under Water Supply Scarcity,” published December 28, 2021.

Use of irrigation systems vary by crop

Wednesday, March 2, 2022

Irrigation methods vary by crop because of differences in production practices, crop value, water source, and soil characteristics. Irrigation application methods can be broadly categorized as either gravity or pressurized systems. Pressurized irrigation systems apply water under pressure through pipes or other tubing, while gravity irrigation systems use field slope to advance water across the field surface. In general, pressurized irrigation systems are more efficient than gravity irrigation systems under most field settings, as less water is lost to evaporation and seepage. Rice has the largest share of acres irrigated by gravity systems, which is related to the flooding requirements of most rice production systems in the United States. Peanuts have the largest proportion of acres irrigated by pressurized systems. Peanut cultivation is concentrated in the Southeastern United States (i.e., Alabama, Georgia, and Florida), where the prevalence of sandy, well-drained soils makes gravity irrigation methods generally unsuitable because of seepage losses. Pressurized systems are also prevalent among high-value specialty crops, such as vegetables and orchards. Pressurized irrigation systems, particularly low-flow micro irrigation systems, are generally more expensive than gravity irrigation systems, precluding their use among lower value crops. Pressurized systems are also more prominent among crops concentrated in regions more reliant on groundwater, including irrigated corn across the Eastern and Central United States. This chart was drawn from the USDA, Economic Research Service report “Trends in U.S. Irrigated Agriculture: Increasing Resilience Under Water Supply Scarcity,” published December 28, 2021.

Large organizations deliver 80 percent of off-farm irrigation water

Thursday, February 17, 2022

Irrigation delivery organizations, such as irrigation districts, ditch companies, mutuals and acequias, provide water to farms and ranches and can vary in size. The USDA 2019 Survey of Irrigation Organizations collected data about them in the 24 States where these organizations are most common. Analysis of the survey data indicated that most irrigation organizations are small or medium in scale based on the number of agricultural acres they serve. An estimated 44 percent serve fewer than 1,000 irrigable acres, and 40 percent serve between 1,000 and 10,000 acres. However, most land and off-farm irrigation water are supplied by large delivery organizations, which serve more than 10,000 acres. While they represent only 16 percent of organizations, they serve 78 percent of irrigated acres with off-farm water and deliver 80 percent of off-farm water. This chart appears in the ERS report Irrigation Organizations: Drought Planning and Response, release January 2022.

Per acre water use in irrigated farmland shows a declining trend

Wednesday, January 19, 2022

The importance of irrigation for the U.S. agricultural sector has evolved significantly over the past century. Irrigated acreage in the country has grown from fewer than 3 million acres in 1890 to more than 58 million acres in 2017. The expansion of irrigated acreage during this period reflects Federal, State, and local investment in irrigation infrastructure to deliver surface water to farms and ranches. Additionally, this expansion is partly due to advancements in well drilling and pumping technologies, which have facilitated growth in groundwater-based irrigated agriculture. Since 1969, the amount of water used per acre irrigated has decreased substantially. The average water use per acre irrigated was more than 2 acre-feet (1 acre-foot = 325,851 gallons) in 1969, which declined to nearly 1.5 acre-feet by 2018. Efficient water application technologies, such as the transition from gravity-based to pressurized irrigation systems, have driven the reduction in water use per acre of irrigated land. This chart was drawn from the USDA, Economic Research Service report “Trends in U.S. Irrigated Agriculture: Increasing Resilience Under Water Supply Scarcity,” published December 2021.

The distribution of U.S. irrigated acreage has shifted eastward since mid-20th century

Tuesday, January 4, 2022

Regional distribution of U.S. irrigated acreage changed significantly from 1949 to 2017. Trends in irrigated cropping patterns, technological advances, water availability, and changing growing-season weather drove this evolution. The arid Mountain and Pacific regions consistently irrigated the most farmland until 2007, when irrigated acreage in the Northern Plains region surpassed acreage in the Pacific region. Irrigated acreage in the Mountain and Pacific regions remained relatively constant over the 70-year period, despite increasingly limited opportunities for additional water development and increasing competition for water from non-agricultural sectors. The Northern Plains region has experienced the most substantial increase in irrigated acreage, expanding from less than 2 million acres in 1949 to nearly 12 million acres in 2017. The expansion of irrigated acreage in the Northern Plains is related to advances in groundwater pumping technologies, the diffusion of center pivot irrigation application systems, and the region’s abundant aquifer resources. The Southern Plains region experienced similar growth in irrigation until the 1980s, when dwindling groundwater supplies resulted in irrigated acreage declines. The Mississippi Delta and Southeast regions also have expanded irrigated acreage since 1949 reflecting, in part, changing cropping patterns, abundant aquifer water supplies, and producer responsiveness to changing precipitation levels during growing seasons. This chart was drawn from the USDA, Economic Research Service report Trends in U.S. Irrigated Agriculture: Increasing Resilience Under Water Supply Scarcity, published December 2021.

Irrigation delivery organizations use a variety of methods to calculate on-farm water use

Monday, December 13, 2021

Irrigation organizations use a variety of methods to calculate on-farm water use so they can accurately track water use within their delivery systems. The methods used to calculate on-farm water use partially determine ways organizations can price water deliveries. For example, implementing volumetric water pricing is difficult unless organizations can directly meter on-farm water use. According to data collected in the USDA’s 2019 Survey of Irrigation Organizations, about 44 percent of irrigation water delivery organizations use direct metering to calculate on-farm water use, and about 42 percent of organizations use time-of-use estimation to determine water deliveries. The time-of-use method estimates the volume of water delivered based on the duration of deliveries and the characteristics of the conveyance infrastructure. About 17 percent of organizations calculate water deliveries based on self-reporting from irrigated farms and ranches. Many organizations use more than one method to determine on-farm water use. This chart was drawn from the USDA, Economic Research Service report Irrigation Organizations: Water Storage and Delivery Infrastructure, published October 2021.

Large irrigation organizations are most likely to own water storage infrastructure

Monday, November 29, 2021

Water storage infrastructure includes dams and reservoirs that provide a way to store water across seasons and years to meet the demands of irrigators. According to data collected in the USDA’s 2019 Survey of Irrigation Organizations, less than 20 percent of water delivery organizations own and manage their own water storage reservoirs. The remaining water delivery organizations rely on natural streamflow or storage infrastructure owned by State or Federal agencies or other irrigation organizations. Large irrigation organizations, defined as those organizations that serve more than 10,000 irrigable acres, are the most likely to own water storage infrastructure. Almost 37 percent of large irrigation organizations have at least one water storage reservoir. Meanwhile, 21 percent of medium organizations and 10 percent of small organizations, have at least one reservoir. Storage infrastructure is particularly important in snowpack-dependent basins where the timing of spring runoff does not align with peak irrigation water demand. The role of water storage infrastructure will be critical as snowpack decreases, snowmelt runoff shifts to earlier in the growing season, and water demand increases. This chart can be found in the USDA, Economic Research Service report Irrigation Organizations—Water Storage and Delivery Infrastructure, published October 19, 2021.

Cost cited as major reason for not lining canals that carry water to farms, ranches in 2019

Wednesday, November 3, 2021

Irrigation organizations that deliver water to farms and ranches use main and lateral canals, tunnels, and pipelines to transport water from natural waterways, reservoirs, or other infrastructure to irrigated farms and ranches. Transporting water to farms and ranches can result in conveyance losses, or water that is unavailable for irrigation use because of evaporation or seepage. Lining water canals with quasi-impermeable materials, such as concrete or plastic membranes, can reduce conveyance losses as less water is lost to seepage. However, the cost of lining canals may be prohibitively high for many irrigation organizations. According to data collected in the USDA’s 2019 Survey of Irrigation Organizations, almost 76 percent of water delivery organizations cite expense as a reason for leaving conveyance infrastructure unlined. In some scenarios, lining canals may not be feasible or warranted. For example, unlined canals may beneficially recharge aquifers or soil and geologic attributes may minimize seepage losses. A smaller percentage of organizations cite those as reasons for not lining main and lateral canals. This chart can be found in the USDA, Economic Research Service report, Irrigation Organizations—Water Storage and Delivery Infrastructure, published October 19, 2021.

Use of pressurized irrigation systems in the western United States roughly doubled from 1984 to 2018

Monday, September 13, 2021

There are two methods to apply irrigation water to crops: gravity or pressurized irrigation systems. Gravity irrigation systems use on-field furrows, basins, or poly-pipe to advance water across the field surface through gravity means only. Pressurized systems apply water under pressure through pipes or other tubing directly to crops (e.g., sprinkler and micro/drip irrigation systems). Under many field conditions, pressurized irrigation systems use water more efficiently than gravity systems, as less water is lost to evaporation, deep percolation, and field runoff. Over the last 30 years, the number of acres irrigated using pressurized irrigation systems roughly doubled while the acreage irrigated using gravity systems declined substantially in the 17 Western States. In 2018, 72 percent of all irrigated cropland acres (28.96 million acres out of 40.31 million acres of total irrigated area) in 17 Western States used pressurized irrigation systems, up from 37 percent in 1984. This chart appears in the USDA, Economic Research Service topic page for Irrigation & Water Use, updated August 2021.

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.

USDA’s Conservation Reserve Enhancement Program in Kansas largely attracts participants with higher rates of groundwater depletion

Wednesday, October 21, 2020

Agriculture in the semi-arid region overlying the High Plains Aquifer, which spans parts of eight states, relies on groundwater. In several areas, significantly more groundwater is extracted than is returned to the aquifer each year, leading to declining water levels. In Kansas, USDA’s Conservation Reserve Enhancement Program (CREP) specifically focuses on retiring irrigated cropland to reduce stress on limited water resources. To represent the amount of water that retired rights would have used in the absence of CREP, in effect the amount of use reduced by the program, ERS researchers used a group of 98 unenrolled farmers similar to 98 enrolled farmers based on factors like farm size, crops grown, and soil quality. Trends of unenrolled matched farmers are largely representative of the average unenrolled farmer in the Western District, where most enrollments have occurred, and which has experienced the most significant aquifer depletion. From 1996 to 2017, unenrolled matched farmers decreased their water use by 0.94 percent a year relative to 1996 levels, compared to 0.64 percent a year for the average unenrolled farmer in the Western District. Furthermore, although unenrolled matched farmers initially experienced more rapid depletion, declines in saturated thickness have been very similar for the two groups since 2008. This chart appears in the October 2020 Amber Waves feature, “Incentives to Retire Water Rights Have Reduced Stress on the High Plains Aquifer.”

Households are the largest users of fossil fuels in the U.S. food system

Wednesday, August 12, 2020

Knowing where natural resource use accumulates is fundamental to understanding what factors influence resource-use decisions. A recent Economic Research Service (ERS) study estimated natural resource use by the U.S. food system in 2007 (2007 data were the latest available with the level of detail needed for the analysis). Farm production was the smallest user of fossil fuels (12 percent of fossil fuel use); households were the largest users (35 percent). Over 40 percent of greenhouse gas emissions in food production were from farms and ranches, followed by households, and then companies that distribute and market food. For forest products, the greatest use occurred during food processing and packaging, with paper-based packaging accounting for most of this use. Farm production was the dominant user of freshwater withdrawals due to irrigation, but slightly over a third of water use by the food system in 2007 occurred after the farm, including in household kitchens (20 percent) and in the energy industry (12 percent). This chart appears in the ERS report, Resource Requirements of Food Demand in the United States, and Amber Waves article, “A Shift to Healthier Diets Likely To Affect Use of Natural Resources,” May 2020.

U.S. food system accounted for between 7 to 28 percent of the Nation’s 2007 use of five natural resources

Thursday, May 28, 2020

Conserving natural resources starts with identifying where they are used. A recent Economic Research Service (ERS) study examined how much of 5 of the Nation’s natural resources were used in 2007 to feed Americans aged 2 and above. (2007 data were the latest available with the level of detail needed for the analysis.) The researchers looked at the entire U.S. food system from production of farm inputs—such as fertilizers and feed—through points of consumer purchases in grocery stores and eating-out places to home kitchens. Their estimates show that agricultural land use in the U.S. food system was 25.5 percent of the country’s 2.3 billion acres of total land. Although the study does not account for other food-related land use, such as by forestry and mining industries serving the food system, it does show that about half of agricultural land is dedicated to food production for the U.S. market, and the other half was devoted to nonfood crops, like cotton and corn for producing ethanol, and to export crops, like soybeans. The U.S. food system also accounted for an estimated 28 percent of 2007’s freshwater withdrawals, 11.5 percent of the fossil fuel budget, and 7.2 percent of marketed forest products. Air is a natural resource that is degraded by the addition of greenhouses gases. The food system accounted for an estimated 18.1 percent of U.S. greenhouse gas emissions in 2007. A version of this chart appears in the ERS report, Resource Requirements of Food Demand in the United States, May 2020 and the Amber Waves feature article, “A Shift to Healthier Diets Likely To Affect Use of Natural Resources.”

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.

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.

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.

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