.
Irrigation in U.S. Agriculture: On-Farm
Technologies and Best Management Practices
Peyton McGee
Research Assistant
Megan Stubbs
Specialist in Agricultural Conservation and Natural Resources Policy
August 21, 2015
Congressional Research Service
7-5700
www.crs.gov
R44158
c11173008
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Summary
Recent threats to water availability as a result of moderate to exceptional drought in several states
have raised questions about agricultural water use and efficiencies across the United States. An
understanding of common irrigation technologies and the impacts of best management practices
in irrigation may be useful to Congress concerning potential policy responses to this issue. As a
major user of water, the agricultural industry’s use of water resources continues to be a focal point
of agriculture policy. Additional demands on water supplies, extreme weather events (e.g.,
prolonged drought), and agricultural market conditions have raised producers’ interest in
investing in irrigation systems. Increased pressure on the industry to reduce its water use has also
drawn interest in the adoption of irrigation technologies and best management practices (BMPs)
as a means of achieving efficiency and potential water savings.
The federal government performs several roles in assisting agricultural producers with irrigation
practices, including financial assistance, technical assistance, research, and monitoring and
reporting. The majority of financial and technical assistance is offered through voluntary
conservation programs that target increased irrigation efficiency. In some cases, improvements in
irrigation efficiency can increase water consumption because farmers increase the number of
irrigated acres or grow more profitable, water-intensive crops. This raises questions about how
and where federal funds are allocated, particularly in areas where water shortages are a concern.
The use and significance of irrigated agriculture varies widely across the United States. Although
policy discussions related to irrigation typically focus on western states—home to roughly 71%
of irrigated farms—irrigation is practiced in all 50 states and is growing in the east. Over time,
there has been a shift in water resources used for irrigation, with an increasing reliance on
groundwater and less on the use of surface water.
The type of irrigation system used has also shifted over time—from a gravity, or flood-type of
irrigation, to potentially more efficient pressurized sprinkler and drip irrigation systems. Pressure
systems account for between 58 to 65% of irrigation systems used in the United States and
include applicators such as center pivot, surface drip, slide roll or wheel move, and micro
sprinkler. Gravity flow, which includes furrow, and controlled and uncontrolled flooding,
accounts for approximately 35 to 42% of irrigation systems in the United States. Irrigation BMPs
center around how water is managed on a farm and includes on-farm conveyance, irrigation
scheduling, and application methods. Increasingly, precision technologies (e.g., drones, sensor
networks, data analytics, etc.) are becoming a common part of many irrigation systems because of
their potential to increase efficiencies and reduce costs.
The use of irrigation technology and BMPs bring both benefits and costs. The control of water
application achieved through irrigation systems can create higher yields and allow the production
of higher value crops, while potentially reducing some production costs. The additional cost of
installing and maintaining these systems, however, can present a barrier to implementing BMPs.
Accounting for variations in the local climate, soil type, water quality, and water availability may
also challenge adoption of irrigation technologies and BMPs.
Congressional Research Service
c11173008
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Contents
Irrigation Trends in the United States .............................................................................................. 9
National Trends ......................................................................................................................... 9
On-Farm Trends ...................................................................................................................... 10
Irrigation Efficiency ...................................................................................................................... 12
Irrigation Technologies and Best Management Practices (BMPs) ................................................ 14
Pressure Systems ..................................................................................................................... 15
Gravity Systems ...................................................................................................................... 17
Precision Technologies ............................................................................................................ 21
Benefits of BMP Implementation............................................................................................ 22
Barriers to BMP Implementation ............................................................................................ 23
Cost and Financial Considerations .................................................................................... 23
Crop Type .......................................................................................................................... 24
Climate .............................................................................................................................. 25
Soil .................................................................................................................................... 25
Labor and Technology Requirements ............................................................................... 25
Water Quality and Quantity of Applied Water .................................................................. 25
Federal Assistance ......................................................................................................................... 26
Financial Assistance ................................................................................................................ 26
Technical Assistance ............................................................................................................... 28
Research .................................................................................................................................. 29
Monitoring/Reporting ............................................................................................................. 29
Figures
Figure 1. Percent of Market Value of Crops Sold from Irrigated Farms, 2012 ............................... 6
Figure 2. Percent Change in Irrigated Acres in the United States, 1997-2013 ................................ 7
Figure 3. Irrigated Acres and Applied Irrigation Water, Western States 1984-2013 ..................... 10
Figure 4. Sources of Applied Irrigation Water in the West and East, 2003-2013 ........................... 11
Figure 5. Irrigation Technologies by Acres and Applied Water by Acre-Feet by Census
Division, 2013 ............................................................................................................................. 11
Figure 6. Irrigation Technologies in Select States, 2013 ............................................................... 13
Figure 7. Sprinkler Irrigation ......................................................................................................... 16
Figure 8. Microirrigation ............................................................................................................... 16
Figure 9. Low-Energy Precision Application Irrigation ................................................................ 16
Figure 10. Laser-Leveling Irrigation Land .................................................................................... 18
Figure 11. Tailwater Recovery and Pump ..................................................................................... 19
Figure 12. Common Irrigation Technologies in the United States ................................................ 20
Figure 13. Soil Moisture Active Passive (SMAP) ......................................................................... 21
Figure 14. Remote Soil Monitoring ............................................................................................... 22
Figure 15. Poly-Pipe Irrigation ...................................................................................................... 22
Figure 16. Farm Bill Irrigation BMPs Funding by Watershed, FY2009-FY2014 ......................... 28
Congressional Research Service
c11173008
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Figure A-1. Irrigation Technologies and Water Use by State, 2013 .............................................. 31
Figure C-1. Farm Bill Irrigation BMPs Funding by State, FY2009-FY2014 ............................... 35
Tables
Table 1. Major Irrigation Technologies: Use in the United States, 2013 ....................................... 17
Table 2. Cost Estimates for Select Irrigation Technologies ........................................................... 24
Table 3. Farm Bill Irrigation BMP Funding by Practice, FY2009-FY2014 .................................. 27
Appendixes
Appendix A. Irrigation Technologies and Water Use .................................................................... 31
Appendix B. Practice Codes and Definitions for Irrigation BMPs ............................................... 32
Appendix C. Irrigation BMPs Funding ......................................................................................... 35
Contacts
Author Contact Information .......................................................................................................... 36
Acknowledgments ......................................................................................................................... 36
Congressional Research Service
c11173008
link to page 6 link to page 7 .
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
griculture is a major user of water in the United States. How the industry utilizes water
resources through irrigation technologies and best management practices continues to be
A a focal point of agriculture policy. Recent droughts and water shortages have resulted in
agricultural producers and conveyance institutions rethinking how water is delivered to and used
on the farm to adjust to water shortages.1 Drought and water shortages affecting farmers’ ability
to irrigate, however, are not isolated to the western United States. Between 2008 and 2013,
irrigation was discontinued on over 470,000 acres of farmland across the United States due to
surface and groundwater shortages.2 Given the increasing demands on water supplies for other
users and uses, especially for the urbanizing West, there are pressures for the agricultural industry
to reduce its water footprint. At the same time, there are other forces (e.g., markets, policies, and
droughts) that are encouraging increased interest in irrigation adoption and efficiency.
Irrigation, generally defined, is the artificial application of water to plants to sustain or enhance
plant growth. There are three primary sources of water for on-farm irrigation: groundwater from
wells (55% of irrigation water applied in 2013), water delivered to farms (35%), and on-farm
surface water (10%).3
The use and significance of irrigated agriculture varies widely across the United States. Five
states (Nebraska, California, Arkansas, Texas, and Idaho) alone represent 52% of the total
irrigated acres nationally.4 As shown in Figure 1, irrigated farms in several western states
(Arizona, California, Idaho, Nevada, New Mexico, Utah, and Wyoming) and two eastern states
(Arkansas and Florida) produce over 89% of the market value of crops sold in those states. In
2012, farms with irrigated land accounted for 50% ($106.3 billion) of the market value of crops
sold in the United States, with roughly 71% of irrigated farms residing in the 17 western states.5
Although the market share of many western states is high, most have seen a reduction in irrigated
acres since 1997 (see Figure 2). At the same time, irrigation in the east is growing, with some
states seeing a percent increase of more than 50% over this same time period.
1 U.S. Department of the Interior, Bureau of Reclamation, “Chapter 4: Agricultural Water Conservation, Productivity,
and Transfers,” Colorado Basin Stakeholders Moving Forward to Address Challenges Identified in the Colorado River
Basin Water Supply and Demand Study: Phase 1 Report, May 2015. http://www.usbr.gov/lc/region/programs/crbstudy/
MovingForward/Phase1Report.html; Stephanie Haugen, “Water worries,” Portland Tribune, June 16, 2015,
http://portlandtribune.com/sl/263813-134762-water-worries; Kaomine Vang and David Zoldoske, Irrigation
Management, California Agricultural Water Stewardship Initiative, http://agwaterstewards.org/index.php/practices/
irrigation_management.
2 U.S. Department of Agriculture (USDA), National Agricultural Statistics Service (NASS), 2013 Farm and Ranch
Irrigation Survey, Table 27: Discontinuance of All Irrigation by Reason: 2013 and 2008,
http://www.agcensus.usda.gov/Publications/2012/Online_Resources/Farm_and_Ranch_Irrigation_Survey/.
3 USDA, NASS, 2013 Farm and Ranch Irrigation Survey, Table 4: Estimated Quantity of Water Applied by Source,
http://www.agcensus.usda.gov/Publications/2012/Online_Resources/Farm_and_Ranch_Irrigation_Survey/.
4 USDA, NASS, Irrigation: Results from the 2013 Farm and Ranch Irrigation Survey, ACH 12-16, November 2014,
http://www.agcensus.usda.gov/Publications/2012/Online_Resources/Highlights/Irrigation/Irrigation_Highlights.pdf.
5 USDA, NASS, 2013 Farm and Ranch Irrigation Survey, Tables 4 and 11, http://www.agcensus.usda.gov/
Publications/2012/Online_Resources/Farm_and_Ranch_Irrigation_Survey/; USDA, NASS, 2012 United States Census
of Agriculture, AC 12-A-51, Washington, DC, May 2014, Table 11: Selected Characteristics of Irrigated and
Nonirrigated Farms: 2012 and 2007, http://www.agcensus.usda.gov/Publications/2012/Full_Report/
Volume_1,_Chapter_1_US/st99_1_011_011.pdf. The 17 western states, also referred to in this report as the West, are
defined by the Bureau of Reclamation and include Arizona, California, Colorado, Idaho, Kansas, Montana, Nebraska,
Nevada, New Mexico, North Dakota, Oklahoma, Oregon, South Dakota, Texas, Utah, Washington, and Wyoming.
Congressional Research Service
5
c11173008
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Figure 1. Percent of Market Value of Crops Sold from Irrigated Farms, 2012
Source: CRS from USDA, National Agricultural Statistics Service (NASS), 2012 United States Census of
Agriculture, AC 12-A-51, Washington, DC, May 2014, http://www.agcensus.usda.gov/Publications/2012/
Ful _Report/Volume_1,_Chapter_1_US/usv1.pdf.
Congressional Research Service
6
c11173008
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Figure 2. Percent Change in Irrigated Acres in the United States, 1997-2013
Source: CRS from USDA, NASS, Quick Stats, http://quickstats.nass.usda.gov/.
Many stakeholders are interested in policies associated with irrigation because of its significance
to U.S. agriculture and water supplies. Drought and heat events, as well as agricultural market
conditions, have raised agricultural producers’ interest in investing in irrigation systems and
improved irrigation practices; these producers often are weighing the benefits of irrigation-related
investments with their costs. Many municipal interests and customers are concerned about
irrigation’s role in regional water demands and how agricultural water use may affect urban water
supplies. These interests would often like to see more judicious use of water in agriculture.6
Environmental interests are concerned about irrigation’s impact on water quality and water source
depletion and resulting impacts on aquatic ecosystems and species. At the same time, agricultural
producers are concerned about possible cuts to their right or access to water, the lack of which
could alter their ability to farm or alter their current system, crop type, or yield.
A report from 1996 by the National Research Council summarized the pressures affecting the
changing nature of U.S. irrigation as follows:7
Water costs and demand for water are rising, which is likely to continue.
Irrigated agriculture, as the largest and most economically marginal user of water
in water-scarce areas, is vulnerable to changing water availability.
The viability of irrigated farming may be threatened by problems, such as
salinization of soils and dependence on nonrenewable water supplies.
6 George Skelton, “Thirsty Crops Should Require State Regulation,” Los Angeles Times, March 22, 2015,
http://www.latimes.com/local/politics/la-me-cap-drought-20150323-column.html; Mark Bittman, “Making Sense of
Water,” New York Times, April 14, 2015, http://www.nytimes.com/2015/04/14/opinion/making-sense-of-water.html.
7 National Research Council, A New Era for Irrigation, 1st ed. (Washington, DC: National Academies Press, 1996).
Congressional Research Service
7
c11173008
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
The quality of irrigation drainage or return flows is sometimes sufficiently
impaired as to limit the future reuse of that water for other purposes, including
environmental uses.
Irrigation systems and management will likely continue to evolve, moving
toward advanced technologies that provide better water control.
The ability of states, Indian tribes, and individual water users to market water
could be central to increasing the flexibility of water allocation, whether for
irrigation or nonirrigation uses.
Agricultural water use and irrigation practices raise a number of policy questions. For example:
Are on-farm irrigation best management practices (BMPs), and the programs that
support them, the most cost-effective use of federal funding? Are there other
areas of the water supply chain or involving water users (e.g., irrigation districts,
municipal, manufacturing, thermoelectric power, etc.) that could provide greater
water conservation more economically and/or in greater quantities?
How is the efficiency of irrigation BMPs at conserving water measured? Could
these efficiencies be incorporated into federal conservation program
implementation and funding allocations?
Should new and emerging precision technologies, such as data analytics and
drones, receive federal assistance similar to the more traditional irrigation BMPs?
What level of priority should these technologies receive, and what level of water
conservation do they provide?
Should conditions be attached to federal funding for irrigation BMPs to limit
agricultural consumption of conserved water (e.g., limiting new irrigated land
from coming into production when federal funds are used to convert to efficient
irrigation systems)? If consumption restrictions were required, what impact
would this have on irrigation BMP adoption? What impact would this have on
voluntary federal conservation program participation? What would the conserved
water be used for, and who controls it? If the conserved water is diverted to
another consumptive purpose (e.g., urban use), is it truly “conserved?”
This report primarily addresses two U.S. on-farm irrigation topics: (1) the adoption of irrigation
technologies and best management practices and (2) water use associated with irrigation. The
report is intended to provide an overview of on-farm irrigation and does not cover storage and
conveyance prior to the farm or how irrigation adoption may alter other farm practices, such as
the use of fertilizers and pesticides or impacts off-farm (e.g., groundwater and surface water
quality concerns).8 While these issues are significant to understanding the full system that
supports irrigated agriculture and the potential environmental impacts of irrigation, they are
beyond the purpose and scope of this report.
8 Irrigation comes with a suite of environmental management challenges and options. A 1982 incident of waterfowl and
shorebird reproductive failures, deformities, and mortalities at the Kesterson National Wildlife Refuge in the San
Joaquin Valley of California is one example that raised attention to the issue of farm irrigation drainwater quality.
Some of the location-specific irrigation drainwater constituents that have been identified as concerns include arsenic,
boron, copper, DDT, mercury, molybdenum, salinity selenium, and zinc (U.S. Department of the Interior, National
Irrigation Water Quality Program, August 2001, http://www.usbr.gov/niwqp/pdf/niwqpbrochure.pdf). The USDA has
identified improvements in irrigation water management as essential to meeting national priorities for reducing
agriculturally induced pollution, such as surface water and groundwater contamination and soil erosion and
sedimentation.
Congressional Research Service
8
c11173008
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Irrigation Trends in the United States
Irrigation has played a significant role in the development and economy of the United States. It
was critical in the settlement of the West and agricultural reinvention after the Dust Bowl. While
irrigation has ancient roots, technological developments (e.g., pumps, plastics, computers, and
sensors) have transformed modern irrigated agriculture.9 The benefits of irrigation for the nation’s
agricultural industry have been expansive; however, the application of irrigation technologies and
the concomitant changes in the industry have not been without their costs. These costs include but
are not limited to associated infrastructure (e.g., dams and conveyance facilities), programs
supporting use (e.g., federal assistance for irrigation investments and efficiency improvements),
and potential effects on other current and future water users and the environment.
National Trends
The two primary measurements of irrigation water use are water withdrawals and water
consumption. While irrigation water withdrawals measure the amount of water applied to lands to
assist in crop and pasture growth, water consumption from irrigation refers to the water that is
taken in by a plant or evaporated without returning to water sources through runoff or percolation.
Although irrigation is the second-largest source of water withdrawals in the United States behind
thermoelectric power, irrigation withdrawals have decreased by 23% since their peak in 1980.10
From 2005 to 2010, irrigation withdrawals dropped 9% nationally.11 It is unclear, however,
whether this decline in withdrawals has led to a decline in water consumption.12 This is because
as irrigation efficiency improves, often less water returns to surface or groundwater supplies
through runoff or percolation.
Brief Glossary of Terms
17 Western States (The West)—Arizona, California, Colorado, Idaho, Kansas, Montana, Nebraska, Nevada, New
Mexico, North Dakota, Oklahoma, Oregon, South Dakota, Texas, Utah, Washington, and Wyoming.
Eastern States (The East)—All contiguous states not included in the 17 western states.
Gravity Irrigation—Irrigation systems that divert water from a source to flood over a crop area via land-forming
measures, including canals, ditches, basins, and furrows.
Microirrigation—Irrigation systems that consist of several types of low-pressure, highly efficient irrigation systems
that apply water directly to the root zone of crops.
Sprinkler Irrigation—Irrigation systems that spray water into the air through a sprinkler or nozzle over a crop
area to provide adequate soil moisture for crops.
9 Modern irrigation methods arose in the United States in the mid-19th century with the settlement of the Utah Great
Salt Lake Basin. In 1902, Congress responded to growing support for federal irrigation assistance in the west by
passing the Reclamation Act, which ultimately led to the construction of over 100 water projects in 17 western states,
making extensive settlement and large-scale irrigation projects on western lands possible.
10 Molly A. Maupin, Joan F. Kenny, and Susan S. Hutson, et al., Estimated Use of Water in the United States in 2010,
U.S. Geological Survey, Circular 1405, November 5, 2014, http://pubs.usgs.gov/circ/1405/.
11 Ibid.
12 There are no recent authoritative national estimates on water consumption. Previously water consumption was
estimated by the U.S. Geological Survey; however, it has not produced consumption estimates since 1985.
Congressional Research Service
9
c11173008
link to page 7 link to page 10 link to page 20 .
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
On-Farm Trends
As Figure 2 illustrates, changes in the amount of land irrigated across the United States over time
vary by region. Since 2003, only four western states have seen an increase in irrigated acres,
while the rest have seen a reduction. Several eastern states, on the other hand, have seen a
significant increase in irrigated acres over this same time period; seven states increased irrigation
by 50% (Delaware, Georgia, Illinois, Indiana, Mississippi, South Carolina, and Tennessee).
Since the 1980s, farmers shifted from gravity irrigation to pressurized sprinklers and
microirrigation.13 This shift has been especially pronounced in 17 western states, with gravity
irrigation declining from almost 62% of irrigated acres in 1984 to 30% by 2013.14 As shown in
Figure 3, irrigated land in the West increased by 1.7 million acres during this same time period,
while applied irrigation water declined by over 1.37 million acre-feet (AF).15 There have been
Figure 3. Irrigated Acres and Applied Irrigation Water, Western States 1984-2013
80
70
Total Applied
Irrigation Water
60
(Millions of Acre-feet)
50
Total Irrigated Acres
s
(Millions of Acres)
n
40
illio
M
Irrigated Acres -
30
Pressure
(Millions of Acres)
20
Irrigated Acres -
Gravity
10
(Millions of Acres)
0
1984
1988
1994
1998
2003
2008
2013
Source: CRS from Glenn Schaible and Marcel Ail ery, Irrigation and Water Use: Background, USDA, Economic
Research Service (ERS), June 7, 2013, http://www.ers.usda.gov/topics/farm-practices-management/irrigation-
water-use/background.aspx; and USDA, NASS, 2013 Farm and Ranch Irrigation Survey, Tables 4, 29, 30, and 31,
http://www.agcensus.usda.gov/Publications/2012/Online_Resources/Farm_and_Ranch_Irrigation_Survey/.
13 For a brief description of common irrigation technologies, see Figure 12.
14 USDA, NASS, 2013 Farm and Ranch Irrigation Survey, Table 28: Land Irrigated in the Open by Method of Water
Distribution: 2013 and 2008, http://www.agcensus.usda.gov/Publications/2012/Online_Resources/Farm_and_
Ranch_Irrigation_Survey/; U.S. Department of Commerce, Bureau of the Census, 1984 Farm and Ranch Irrigation
Survey, AG84_SR-1, Table 4: Land Irrigated by Method of Water Distribution 1984, June 1986,
http://catalog.hathitrust.org/Record/009152634.
15 An acre-foot (AF) of water is the volume of water it takes to cover one acre of land with a one foot of water. Sources:
USDA, NASS, 2013 Farm and Ranch Irrigation Survey, Tables 4 and 11; and U.S. Department of Commerce, Bureau
of the Census, 1984 Farm and Ranch Irrigation Survey, AG84_SR-1, Table 6: Estimated Quantity of Water Applied by
Source 1984, June 1986, http://catalog.hathitrust.org/Record/009152634.
Congressional Research Service
10
c11173008
link to page 31 
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Figure 4. Sources of Applied Irrigation Water in the West and East, 2003-2013
80
70
60
t
-Fee 50
Water Delivered
cre
to Farms
f A 40
o
On-Farm
s
n
Surface Water
30
illio
Groundwater
M
From Wells
20
10
0
West
East
West
East
West
East
2003
2008
2013
Source: CRS from USDA, NASS, 2013 Farm and Ranch Irrigation Survey, http://www.agcensus.usda.gov/
Publications/2012/Online_Resources/Farm_and_Ranch_Irrigation_Survey/; and USDA, NASS, 2008 Farm and
Ranch Irrigation Survey, http://www.agcensus.usda.gov/Publications/2007/Online_Highlights/
Farm_and_Ranch_Irrigation_Survey/.
Notes: The West refers to the 17 western states previously identified, and the East refers to all contiguous
states not included in the 17 western states. Data does not include water withdrawals from institutional,
research, and experimental operations or horticultural crops grown under protection in greenhouses and other
protective structures that regulate light, shade, and temperature.
Figure 5. Irrigation Technologies by Acres and Applied Water by Acre-Feet by Census
Division, 2013
s 16
40
t
cre
-Fee
f A
o 14
35
cre
s
n
f A
o
s
illio 12
30
n
M
illio
M
10
25
Microirrigation
(Millions of Acres)
8
20
Sprinkler Irrigation
(Millions of Acres)
6
15
Gravity Irrigation
(Millions of Acres)
4
10
2
5
0
0
Source: CRS from USDA, NASS, 2013 Farm and Ranch Irrigation Survey, Tables 6 and 28,
http://www.agcensus.usda.gov/Publications/2012/Online_Resources/Farm_and_Ranch_Irrigation_Survey/.
Notes: Divisions are based on the nine U.S. Census Bureau Divisions. For a state-by-state breakdown, see
Appendix A. Data do not include water withdrawals or irrigation methods from institutional, research, and
experimental operations or horticultural crops grown under protection.
Congressional Research Service
11
c11173008
link to page 11 link to page 11 link to page 11 link to page 11 .
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
fluctuations in the amount of irrigation water applied over time with the current trend of decline
in water application beginning in 1998. Figure 4 shows that although irrigation withdrawals from
on-farm surface water and water delivered to farms in the West has decreased by about 2.5
million and 1.2 million AF, respectively, since 2003, groundwater withdrawals have increased by
over 740,000 AF. Even with this overall decline in irrigation withdrawals, irrigation withdrawals
remain highest in the western-most portions of the United States (Figure 5).16
Growth in irrigated acres in the West is small when compared to increases in the East. Since
1984, irrigated land in eastern states has grown by over 8.7 million acres.17 Figure 4 shows that
groundwater withdrawals have been the primary withdrawal source for irrigation in eastern states.
Withdrawals peaked in 2008, with an overall increase of 4.3 million AF since 2003. This trend in
increased irrigated acres in the East has been attributed to increased commodity prices and yield,
drought episodes, and low-cost access to groundwater.18 In many cases, this expanded use of
groundwater for irrigation has contributed to a decline in aquifer levels and raised environmental
concerns.19
Irrigation Efficiency
While there are many definitions that can be used for this term, irrigation efficiency in this report
refers to the percentage of applied irrigation water that is beneficially used and not lost to
evaporation or seepage during on-farm conveyance, percolation, or runoff.20 This is determined
by several factors, including irrigation system performance, uniformity of water application, and
crop response to irrigation.21 One factor to consider in determining irrigation efficiency is the rate
of evapotranspiration.22 Climate conditions, like length of sunlight hours, intensity of sunlight,
temperature, humidity, wind speed, and canopy development, influence evapotranspiration rates,
which determine the crop water requirement.23 Another determinant of irrigation efficiency is the
water conveyance system. Irrigation canals that are not well constructed or maintained can lead to
conveyance losses of up to 50%.24
16 Although the West North Central division (Figure 5) had the highest number of irrigated acres in 2013, total acre-
feet applied was half of water use in the Pacific division. This may be influenced by, but not limited to, climate
conditions, soil infiltration rates, and the irrigation efficiency of sprinkler systems, which make up the majority of
systems used in the West North Central division.
17 U.S. Department of Commerce, Bureau of the Census, 1984 Farm and Ranch Irrigation Survey, Table 2,
http://catalog.hathitrust.org/Record/009152634; and USDA, NASS, 2013 Farm and Ranch Irrigation Survey, Table 2,
http://www.agcensus.usda.gov/Publications/2012/Online_Resources/Farm_and_Ranch_Irrigation_Survey/.
18 Glenn Schaible and Marcel Aillery, Irrigation and Water Use: Background, USDA, Economic Research Service
(ERS), June 7, 2013, http://www.ers.usda.gov/topics/farm-practices-management/irrigation-water-use/
background.aspx.
19 Ibid.
20 This report does not cover the efficiency of off-farm conveyance systems related to irrigation.
21 B.A. Stewart and Terry A. Howell, “Irrigation Efficiency,” in Encyclopedia of Water Science (New York: Marcel
Dekker, 2003), pp. 467-472.
22 Evapotranspiration refers to evaporation for the soil surface and transpiration from plants.
23 Martin Burton, Irrigation Management: Principles and Practices (Oxfordshire: The Centre for Biosciences and
Agriculture International, 2010), http://www.lrc.tnu.edu.vn/upload/collection/brief/7698_9781845935160.pdf.
24 Karina Schoengold and David Zilberman, “Chapter 58: The Economics of Water, Irrigation, and Development,” in
Handbook of Agricultural Economics, ed. Robert Evenson & Prabhu Pingali, vol. 3 (Elsevier B.V., 2007), pp. 2933-
2977.
Congressional Research Service
12
c11173008
link to page 6 link to page 7 link to page 13 .
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Efficient irrigation systems are often thought of as allowing the same level of crop production as
less efficient systems while leaving additional water in the hydrological system for further use
downstream. Studies have shown, however, that in some cases efficient irrigation systems may
lead to greater water consumption.25 In a study of irrigation subsidies, researchers found that
increasing water conservation subsidies for drip irrigation in the Upper Rio Grande Basin would
increase water consumption and crop yield while also increasing acreage irrigated.26 While some
case studies support this, it remains unclear if expanded irrigation resulting from water
conservation occurs nationwide and to what extent.
Microirrigation may be more efficient than gravity irrigation, but gravity irrigation typically
consumes less water than microirrigation. This is because the majority of water that is not lost to
evapotranspiration through gravity irrigation is returned to surface or groundwater sources
Irrigation Technologies from State to State
The types of irrigation systems most commonly used and the amount of land irrigated can vary widely from state to
state. Figure 6 highlights this difference in select states across the country. Arkansas irrigates more acres than all but
two states (i.e., Nebraska and California) and uses gravity irrigation for over 77% of irrigated acres, while using
microirrigation on just 0.5% of irrigated land. New Hampshire, on the other hand, uses microirrigation (51%) and
sprinkler irrigation (46%) on the majority of irrigated land in the state while using gravity irrigation on only 3% of
irrigated acres. Although the state only irrigated 4,500 acres in 2013, which is a very small percentage of overall
irrigated acres in the United States, New Hampshire is the only New England state to see irrigation grow by more
than 35% since 1997 and have irrigated farms produce over 60% of the market value of crops sold in the state in
2012.27 California, Nebraska, Georgia, and Michigan are highlighted because they are major irrigation-using states
within their respective regions.
Figure 6. Irrigation Technologies in Select States, 2013
Distribution of technologies as a proportion of total irrigated acres per state, in millions of acres
25 Frank A. Ward and Manuel Pulido-Velazquez, “Water Conservation in Irrigation Can Increase Water Use,”
Proceedings of the National Academies of Sciences, vol. 105, no. 47 (2008), pp. 18215-18220, http://www.pnas.org/
content/105/47/18215.full; Reagan M. Waskom, “Water Sustainability in Agriculture: Optimizing Agricultural Water
for Food, the Environment and Urban Use,” Plenary Session at the National Agricultural Biotechnology Council
(NABC Report 24), Ithaca, NY, 2012, pp. 185-194, http://nabc.cals.cornell.edu/Publications/Reports/nabc_24/
24_4_2_Waskom.pdf; Robert G. Evans and E. John Sadler, “Methods and Technologies to Improve Efficiency of
Water Use,” Water Resources Research, vol. 44 (July 29, 2008), http://onlinelibrary.wiley.com/doi/10.1029/
2007WR006200/epdf; Schoengold and Zilberman, 2007; and Schaible and Aillery, 2013.
26 Ward and Pulido-Velazquez, 2008.
27 See Figure 1 and Figure 2.
Congressional Research Service
13
c11173008
link to page 31 
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Source: CRS from USDA, NASS, 2013 Farm and Ranch Irrigation Survey, Tables 29, 30, and 31,
http://www.agcensus.usda.gov/Publications/2012/Online_Resources/Farm_and_Ranch_Irrigation_Survey/.
Notes: For related statistics on all states, see Appendix A
through runoff and deep percolation.28 This means that water that is not taken in by plants through
evapotranspiration could potentially be put to subsequent beneficial use.29 Additionally, even if
measures are taken to limit increased water consumption (e.g., limiting additional irrigated crop
acreage after conversion to efficient irrigation systems), efficient irrigation technologies may
encourage farmers to grow more profitable, water-intensive crops. 30 This means that adopting
more-efficient irrigation technologies may not necessarily result in less water consumed overall.
Irrigation Technologies and Best Management
Practices (BMPs)
A common classification for irrigation systems based on energy and pressure requirements
divides irrigation methods into two categories: pressure systems and gravity systems.31 These
systems are differentiated from each other by the method used to deliver water to crops and cover
28 Ward and Pulido-Velazquez, 2008.
29 A net increase in recharge from surface irrigation only occurs if irrigation withdrawals come from surface water
sources. Another consideration of groundwater depletion is soil type. For example, fine-grained soils, commonly found
in the Central High Plains, limit groundwater recharge from irrigation water. Further, local irrigation efficiency
estimates do not necessarily reflect efficiency levels at a basin scale so wide-scale averages should be taken with the
knowledge that efficiency levels may vary from location to location. For more information, see Bridget R. Scanlon,
Claudia C. Faunt, Laurent Longuevergne, et al., “Groundwater Depletion and Sustainability of Irrigation in the US
High Plains and Central Valley,” Proceedings of the National Academies of Science, vol. 109 no. 24 (2012), pp. 9320-
9325, http://www.pnas.org/content/109/24/9320.full; and Chris Perry, Pasquale Steduto, and Richard G. Allen, et al.,
“Increasing Productivity in Irrigated Agriculture; Agronomic Constraints and Hydrological Realities,” Agricultural
Water Management, vol. 96, no. 11 (November 2009), pp. 1517-1524, http://dx.doi.org/10.1016/j.agwat.2009.05.005.
30 Evans and Sadler, 2008.
31 M. H. Ali, Practices of Irrigation and On-Farm Water Management: Volume 2 (New York: Springer, 2011).
Congressional Research Service
14
c11173008
link to page 32 link to page 16 link to page 16 link to page 17 link to page 20 .
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
most types of irrigation systems in the United States. While these two categories cover basic
irrigation, precision technologies to increase irrigation efficiency and reduce costs complement
these systems and are increasingly becoming a common part of modern irrigation systems.
Best management practices (BMPs) for irrigation center around how water is managed on a farm,
including improved conveyance, irrigation scheduling, and application methods. The BMPs
discussed below are based on select practices identified by USDA’s Natural Resources
Conservation Service (NRCS). Not all irrigation technologies are considered BMPs, and those
listed do not constitute a recommendation or endorsement. Additionally, some BMPs listed could
apply to both pressure and gravity irrigation systems, while others are limited to one type of
system.32 The success or failure of a BMP depends on a number of factors and in some cases
requires the application of more than one practice. For a more extensive list of BMPs, see
Appendix B.
Pressure Systems
Pressure systems pump water through tubing or pipes where water is applied to crops through an
applicator like a sprinkler or perforated pipe. Pressure systems are commonly separated into two
sub-categories: sprinkler and microirrigation systems. Sprinkler irrigation (Figure 7) uses high-
to medium-pressure systems to spray water through applicators, creating artificial precipitation,
while microirrigation (Figure 8) uses low-pressure systems to apply water directly to the root
zone of crops. As shown in Table 1, pressure irrigation systems make up roughly 58-65% of
irrigation systems used in the United States. Major pressure systems include center pivot, linear
move tower, solid set or permanent, slide roll or wheel move, big gun or traveler, hand move, and
drip, trickle, or low-flow micro sprinklers (Figure 12). These systems are generally more efficient
than gravity systems and can be used to grow most crops.33 Although the operational labor
requirement for these systems can be low, the initial investment costs can be high.34
32 For example, irrigation water management plans may be developed on both pressure and gravity irrigation systems.
Sprinkler irrigation, however, is generally limited to pressure systems.
33 Ali, 2011.
34 Ibid; Kenneth H. Solomon, Irrigation Notes: Irrigation System Selection, Center for Irrigation Technology, CATI
Publication No. 880105, Fresno, CA, January 1988, http://cwi.csufresno.edu/wateright/880104.asp.; Burton, 2010.
Congressional Research Service
15
c11173008
link to page 20 link to page 20 
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Irrigation Water Management Plan
Figure 7. Sprinkler Irrigation
An irrigation water management plan requires
intentional preparation to manage the timing
and application of water through irrigation
systems in order to maintain appropriate soil
moisture levels, reduce soil erosion,
maximize plant growth, lower energy
consumption, and increase water efficiency.
This plan may include several irrigation
BMPs: microirrigation, sprinkler irrigation,
ditch lining, land leveling, tailwater recovery,
etc.
Source: USDA NRCS, “Sprinkler System: Practice
Introduction.”
Notes: A center pivot irrigation system.
Sprinkler Irrigation
A sprinkler system is a general term to describe the most common types of pressure irrigation
systems like center pivot, side roll, and linear move tower irrigation (Figure 12). These systems
spray water into the air through a sprinkler or nozzle over a crop area to provide adequate soil
moisture for crops. Sprinkler systems are also used for crop cooling, frost protection, and dust
control.
Figure 8. Microirrigation
Microirrigation
Microirrigation consists of several types of
low-pressure, highly efficient irrigation
systems including surface drip, micro
sprinkler, and sub-surface drip irrigation
(Figure 12). It is typically a more efficient
irrigation method compared to sprinkler and
gravity irrigation because it applies water
directly to the root zone of crops.
Source: USDA NRCS, “Conservation Practice
Figure 9. Low-Energy Precision
Standard Overview: Irrigation System, Microirrigation
Application Irrigation
(441).”
Notes: Surface drip irrigation system.
Low-Energy Precision Application
Irrigation
This enhancement converts standard center
pivot irrigation systems to low-energy
precision application (LEPA) irrigation
systems. LEPA systems apply water directly
into circular furrows through nozzles placed
close to the soil surface to reduce evaporation
losses and energy consumption.
Source: USDA NRCS.
Congressional Research Service
16
c11173008
link to page 20 .
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Table 1. Major Irrigation Technologies: Use in the United States, 2013
Irrigated Acres
Farms
(In Thousands)
36,200-39,800
Pressure Systems
122,000
(58%-65%)
Center Pivot
57,000
27,900
Surface Drip
41,000
2,600
Side Roll or Wheel Move
17,000
1,900
Solid Set and Permanent
21,000
1,500
Low-Flow Micro Sprinklers
15,000
1,300
Hand Move
30,000
800
Sub-Surface Drip
6,000
800
Linear Move Tower
5,000
600
Big Gun or Traveler
8,000
600
Other Sprinkler System
12,000
1,700
Other Drip, Trickle, or Low-Flow Micro Systems
4,000
300
21,500-26,200
Gravity Systems
85,000
(35%-42%)
Furrow
43,000
10,500
Controlled Flooding
37,000
8,500
Uncontrolled Flooding
12,000
1,800
Other Gravity Systems
6,000
800
Total
207,000
57,700-66,000
Source: CRS from USDA, NASS, 2013 Farm and Ranch Irrigation Survey, Tables 29, 30, and 31,
http://www.agcensus.usda.gov/Publications/2012/Online_Resources/Farm_and_Ranch_Irrigation_Survey/; Mol y
A. Maupin, Joan F. Kenny, and Susan S. Hutson, et al., Estimated use of water in the United States in 2010, U.S.
Geological Survey, Circular 1405, November 5, 2014, http://pubs.usgs.gov/circ/1405/.
Notes: All numbers are rounded estimates derived from USDA or USGS data. This is not a comprehensive list
of all irrigation technologies used in the United States. These are major irrigation systems used in the United
States as designated by the 2013 Farm and Ranch Irrigation Survey. For definitions of each irrigation method, see
Figure 12. USGS data is used for the estimated range of irrigated acres using pressure or gravity systems, and
does not include statistics on specific irrigation system subcategories.
Gravity Systems
Gravity systems, which make up 35 to 42% of irrigation systems in the United States, divert
water from a source to flood over a crop area via land-forming measures, including canals,
Congressional Research Service
17
c11173008
link to page 20 link to page 18 
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
ditches, basins, and furrows (Figure 12). While controlled flooding methods, like basin irrigation,
border irrigation, and furrow irrigation, use land-forming measures to increase efficiencies,
uncontrolled flooding, which is the oldest and simplest form of irrigation, does not.35 The
irrigation efficiency of gravity systems is generally less efficient than pressure systems.36 These
systems can have a low to medium initial investment cost and a medium to high operational labor
requirement. Most gravity systems are suited for close-growing crops, like rice. Furrow irrigation
systems, however, may be used for row crops like potato and corn.
Irrigation Land Leveling
Figure 10. Laser-Leveling Irrigation Land
Irrigation land leveling (Figure 10) is the
process of reshaping a field to make sure
water is applied uniformly to a crop area
without creating puddles in low sections and
dry spots in high sections. Land leveling can
increase gravity irrigation efficiency, reduce
erosion, and prevent water logging of soil or
crops.
Field Ditch, Canal, or Lateral
Source: Tim, McCabe, USDA NRCS.
A field ditch, canal, or lateral is a commonly
used method of delivering water from a source to an irrigation system through permanent
channels.
Irrigation Ditch Lining
Irrigation ditch lining is a lining installed in a canal, lateral, or ditch to limit water loss due to
seepage while in transit to a crop area for application. Canal linings can increase conveyance
efficiency by an amount that can vary based on soil type and length of the canal.37 Ditch lining
may be constructed from numerous materials, including concrete, PVC, and polypropylene.38
35 Burton, 2010.
36 Ali, 2011.
37 Food and Agriculture Organization (FAO), Irrigation Water Management: Irrigation Scheduling, Training Manual
no. 4, Rome, 1989, “Annex I: Irrigation Efficiencies,” http://www.fao.org/docrep/t7202e/
t7202e08.htm#annex%20i:%20irrigation%20efficiencies.
38 Robert Burns, What’s the Best Irrigation Canal Liner? Texas A&M University Department of Biological and
Agricultural Engineering, May 24, 2012, http://baen.tamu.edu/2012/05/whats-the-best-irrigation-canal-liner/.
Congressional Research Service
18
c11173008
link to page 19 
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Figure 11. Tailwater Recovery and Pump
Tailwater Recovery
Tailwater recovery refers to reusing excess
water from gravity irrigation that is not
initially infiltrated into the soil. To avoid
potential water contamination through runoff
or waterlogging of crops at the end of a slope,
a tailwater recovery system may be built to
convey water back to the irrigation system for
reuse through a pump and pipeline or ditch
system (Figure 11).
Source: USDA NRCS.
Irrigation Reservoir
An irrigation reservoir provides a storage place for water to use for irrigation. The size of the
reservoir depends on how much water is available and needed for irrigated crops, and the
reservoir water level may be maintained by surface or groundwater. Irrigation reservoirs may be
built by constructing a dam, embankment, pit, or tank.
Congressional Research Service
19
c11173008
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Figure 12. Common Irrigation Technologies in the United States
Source: CRS and USDA NRCS.
Congressional Research Service
20
c11173008
link to page 21 
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Precision Technologies
Figure 13. Soil Moisture Active Passive
(SMAP)
The incorporation of precision technologies
into the agricultural industry has grown
rapidly in recent years, especially in
irrigation. Precision technologies, such as
satellite data, sensor networks, data analytics,
and drones, increase irrigation efficiency and
have been reported to reduce input costs and
increase crop yield.39 Over the last several
years, technology companies have become
increasingly involved in the agricultural
sector, offering technology and data services
Source: NASA, 2014.
to help farmers maximize profits.40
Notes: Artist’s rendering of NASA’s Soil Moisture
Active Passive (SMAP).
Satellite Data
A collaborative project between the NASA Jet Propulsion Laboratory and USDA ARS Hydrology
and Remote Sensing Laboratory recently launched a satellite under the mission title SMAP (Soil
Moisture Active Passive) (Figure 13).41 Once calibrated, this satellite will be able to gather soil
moisture data from around the world without the use of terrestrial sensors or other field
measurements. Governments and agricultural producers could be able to use this data to better
inform decisions on when, where, and how much applied irrigation water may be beneficial.42
Drones43
Unmanned aerial vehicles (i.e., drones) can be used for aerial imagery and data collection; the
information can then be combined with software to help identify trends to show how irrigation
can be adjusted.
39 American Farm Bureau Federation, AFBF Data Privacy Survey Final Results, October 21, 2014, http://www.fb.org/
tmp/uploads/AFBF_Final_Big_Data_Survey_Highlights_9-8-2014.pdf.
40 See Nanette Byrnes, “Internet of Farm Things,” MIT Technology Review, May 21, 2015,
http://www.technologyreview.com/news/537596/internet-of-farm-things/; Katie Fehrenbacher, “How Water
Technology Can Help Farmers Survive California’s Drought,” Fortune, June 1, 2015, http://fortune.com/2015/06/01/
water-drought-californias/; and Dan Bigman, “Farming and Tech: Two Sides of California Converging to Bring More
to the Table,” Forbes, April 21, 2015, http://www.forbes.com/sites/danbigman/2015/04/21/farming-and-tech-two-
sides-of-california-converging-to-bring-more-to-the-table/.
41 For more information, visit the official SMAP website at http://smap.jpl.nasa.gov/.
42 Personal communication with personnel at the USDA ARS Hydrology and Remote Sensing Laboratory on June 24,
2015.
43 Section 333 of the FAA Modernization and Reform Act of 2012 (H.R. 658) allowed commercial drones to fly with
prior approval. On February 15, 2015, the Department of Transportation and Federal Aviation Administration
announced new proposed rules for small unmanned aircraft systems that is reported to be finalized by June 2016, which
will set guidelines that allow the commercial operation of drones without individual approval.; see http://www.faa.gov/
news/press_releases/news_story.cfm?newsId=18295 and http://www.reuters.com/article/2015/06/17/us-usa-drones-
congress-idUSKBN0OX1P020150617.
Congressional Research Service
21
c11173008
link to page 22 link to page 22 link to page 22 
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Figure 14. Remote Soil Monitoring
Sensor Networks and Data Analytics
Sensor networks can be used to monitor plant
water status, plant evapotranspiration, or
volumetric water content of the soil. Data
analytics refers to the use of real-time data on
energy consumption, environmental
conditions, and information gathered from
these sensor networks to improve decisions.
This information can then be used for
irrigation system automation, which adjusts
the amount and frequency of water applied
based on the data gathered (Figure 14).
Source: Jeff Vanuga, USDA, NRCS.
Regional Weather Networks
Information from regional weather networks can be used to track crop evapotranspiration. By
combining this information with precipitation and soil moisture data, an accurate irrigation
schedule can be established.
Remote Monitoring Notification of Irrigation Pumping Plants
A remote monitoring notification system wirelessly transfers real-time information to alter
irrigation operations (e.g., altering pumping). Remotely collected information can help reduce
and prioritize field visits and reduce overall water applied to fields.
Computerized Hole Selection for
Figure 15. Poly-Pipe Irrigation
Poly-Pipe
Poly-pipe is used in furrow irrigation and is a
flexible plastic pipe made from polyethylene
resins that expand when full of water.
Computer software is used to optimize hole
sizes for poly-pipe, which can decrease
applied water and irrigation runoff (Figure
15).
Benefits of BMP
Implementation
Source: USDA, NRCS, Water Quantity Enhancement
Activity, WQT12, October 2, 2014.
The implementation of irrigation BMPs can
further increase irrigation efficiency by creating greater precision for water application. This can
reduce the cost of production and ensure that all areas of a field are more evenly watered. On
average, irrigated yields are roughly double that of non-irrigated crops.44 As a result, irrigation
can also allow producers to grow higher value crops and extend growing seasons. In some cases,
44 Jorge A. Delgado, Peter M. Groffman, and Mark A. Nearing, et al., “Conservation Practices to Mitigate and Adapt to
Climate Change,” Journal of Soil and Water Conservation, vol. 66, no. 4 (July/August 2015), pp. 118A-129A,
http://www.jswconline.org/content/66/4/118A.full.pdf+html.
Congressional Research Service
22
c11173008
link to page 24 .
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
irrigation BMPs enhance production of higher-value specialty crops, including fruits, vegetables,
and nuts, by allowing water to flow to crops only when needed. This not only reduces the cost of
applying water but may prevent problems from overwatering, such as increased disease and pest
activity, root damage, and reduced yields.
The controlled environment of an irrigation system can also be simultaneously used for the
application of other production-related inputs, such as nutrients and pesticides. Depending on the
system, some irrigation BMPs allow synthetic nutrients and pesticides to be mixed with irrigation
water and distributed concurrently. This can also reduce costs and provide more precise
application.
Barriers to BMP Implementation
Irrigation technologies vary across the United States, where implementation choices are
sometimes limited by cost, crop type, climate, soil, labor and technology requirements, and water
quality and quantity available.
Cost and Financial Considerations
Capital and operational costs of irrigation systems can influence the adoption of efficient
irrigation technologies by agricultural producers. For this reason, some have suggested that
adopting efficient irrigation systems is typically not motivated by water conservation, but rather
through potential economic gains of increased crop yield.45 Because of the generally higher costs
of efficient irrigation systems, growers of high-value crops were among the first to adopt drip
irrigation systems, while growers of low-value crops are less likely to invest in costly, albeit more
efficient, irrigation systems.46 According to USDA’s 2013 Farm and Ranch Irrigation Survey
(FRIS), 32% of respondents reported that they could not finance irrigation system improvements,
while 25% reported that improvements would not cover installation costs.47 Table 2 shows that
high-efficiency systems, like micro sprinklers and sub-surface drip, can be far more costly than
gravity systems like furrow irrigation.
Another cost consideration for agricultural producers when selecting an irrigation system is the
cost of developing a water supply. These costs can include drilling a well and operating pumps or
building an on-farm storage facility. The costs of developing a water supply may impact a
producer’s decision to adopt efficient pressure systems. For example, the cost of establishing a
water supply from groundwater, which varies based on pumping depth and energy costs, is
generally more expensive than surface water.48 As a result, high-efficiency pressure systems are
commonly found in areas where there is a heavy reliance on groundwater.49 Alternatively, areas
with adequate surface water supplies are less likely to adopt efficient irrigation systems because
low water development costs make gravity irrigation economically feasible. Growers in drought-
45 Frank A Ward, “Economic Impacts on Irrigated Agriculture of Water Conservation Programs in Drought,” Journal
of Hydrology, October 2013, http://dx.doi.org/10.1016/j.jhydrol.2013.10.024.
46 Robert F. Bevacqua, “Drip Irrigation for Row Crops,” New Mexico University Cooperative Extension Service,
Circular 573, August 2001, http://aces.nmsu.edu/pubs/_circulars/CR573.pdf; and Schaible and Aillery, 2012.
47 USDA, NASS, 2013 Farm and Ranch Irrigation Survey, Table 25, http://www.agcensus.usda.gov/Publications/2012/
Online_Resources/Farm_and_Ranch_Irrigation_Survey/.
48 Dennis Wichelns, “Agricultural Water Pricing: United States,” Organization for Economic Co-Operation and
Development, 2010, http://www.oecd.org/unitedstates/45016437.pdf; and USGS, “Groundwater Use in the United
States,” USGS Water Science School, 2000, http://water.usgs.gov/edu/wugw.html.
49 Schaible and Aillery, 2012.
Congressional Research Service
23
c11173008
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
prone areas that typically rely on surface water, however, are more likely to adopt more efficient
irrigation systems.50
Table 2. Cost Estimates for Select Irrigation Technologies
Est. Capital Cost
per Acre
Low-Flow Micro Sprinklers
$2,800
Sub-Surface Drip
$1,200 - $1,800
Surface Drip
$860
Linear Move Tower
$850
Center Pivot
$340 - $620
Side Roll or Wheel Move
$610
Big Gun or Traveler
$590
Furrow
$210
Source: CRS from T. Scherer, “Selecting a Sprinkler Irrigation System,” NDSU Extension Service (January 2010),
https://www.ag.ndsu.edu/pubs/ageng/irrigate/ae91.pdf; “441 – Irrigation System, Microirrigation,” USDA – Natural
Resources Conservation Service (December 2014), http://efotg.sc.egov.usda.gov/references/public/CO/441.pdf; S.
Amosson et al., “Economics of Irrigation Systems,” Texas AgriLife Extension Service (October 2011),
http://amaril o.tamu.edu/files/2011/10/Irrigation-Bul etin-FINAL-B6113.pdf.
Notes: These cost estimates were taken from specific hypothetical scenarios provided by government agencies
and extension services. These are approximate costs that are meant to give a general idea of the price difference
between different irrigation methods, which may vary due to multiple factors, including but not limited to
location. Capital cost estimates do not include well, pump, and motor costs.
Crop Type
Irrigation system adoption is also determined by the type of crop being irrigated. For example,
because high-pressure sprinklers used on perennial tree crops can saturate the trees and lead to
fruit decay, these crops are better suited for drip irrigation systems.51 While close-growing crops
like rice typically require gravity irrigation, it is less effective for widely spaced field crops that
do not need the total field soil saturation.52 Recent survey data shows that many farmers in the
United States are not able to utilize more efficient irrigation systems because of crop type. In
some cases, this was due to physical field conditions, while other cited a high risk for reduced
crop yields or poorer crop quality.53
50 Eric C. Schuck, W. Marshall Frasier, and Robert S. Webb, et al., “Adoption of More Technically Efficient Irrigation
Systems as a Drought Response,” Water Resources Development, vol. 21, no. 4 (December 2005), pp. 651-662,
http://www.ext.colostate.edu/drought/irr_systems.pdf.
51 Gareth Green, David Sunding, and David Zilberman, et al., “Explaining Irrigation Technology Choices: A
Microparameter Approach,” American Journal of Agricultural Economics, vol. 78, no. 4 (November 1996), pp. 1064-
1072, http://www.jstor.org/stable/1243862.
52Ali, 2011.
53 In 2013, 17% of farmers reported physical field or crop conditions limited improvements, while 16% cited risk of
reduced crop yield or poorer crop quality as a barrier to irrigation efficiency improvements. USDA, NASS, 2013 Farm
and Ranch Irrigation Survey, Table 25, http://www.agcensus.usda.gov/Publications/2012/Online_Resources/
Farm_and_Ranch_Irrigation_Survey/.
Congressional Research Service
24
c11173008
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Climate
Local climate conditions are another limiting factor of irrigation technology adoption. For
example, drip and surface irrigation are typically more effective in windy conditions than
overhead sprinklers.54 In an arid climate, sprinkler irrigation is subject to high levels of
evaporation, and subsurface irrigation can cause soil salinity problems.55 Additionally, climate
conditions affect crop evapotranspiration rates, which can affect an agricultural producer’s
decision for the most appropriate irrigation system.
Soil
The type of soil found in a crop production area can also be a determining factor when selecting
an irrigation system. For example, sandy soils typically require a sprinkler or microirrigation
method because high infiltration rates lower the efficiency of gravity irrigation.56 While loam and
clay soils can accommodate sprinkler, microirrigation, and gravity irrigation, the low infiltration
rates of clay soils make it ideal for gravity irrigation.57 Irrigation water management planning
utilizes soil surveys, which evaluate the characteristics of soil in an area and can be a helpful tool
in designing and implementing irrigation systems.58
Labor and Technology Requirements
The labor-technology trade-off between pressure and gravity systems is another factor to consider
when selecting an irrigation system. Gravity irrigation can be a labor-intensive method compared
to pressure systems and can be utilized with few technological inputs.59 Highly automated
sprinkler and drip systems, on the other hand, can require a high level of technical knowledge and
a fraction of the labor of many gravity systems.60
Water Quality and Quantity of Applied Water
Other barriers limiting irrigation choices include water quality and quantity. Water quality can
dictate the type of irrigation system that can be used. Because sprinkler and drip irrigation carry a
clogging risk, sediment-heavy irrigation water is best suited for gravity irrigation.61 Other water
quality concerns, such as salinity and selenium, can be more effectively managed with sprinkler
or drip irrigation because they offer greater control over the depth of water applied per
irrigation.62 The principal law that deals with water quality concerns in the nation’s streams,
lakes, estuaries, and coastal waters is the Federal Water Pollution Control Act, commonly known
54 Burton, 2010.
55 Ibid. and Ali, 2011.
56 Ali, 2011.
57 Ibid.
58 Soil Survey Division Staff, “Soil Survey Manual,” U.S Department of Agriculture Handbook 18, 1993,
http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ref/?cid=nrcs142p2_054262. Soil type information is available
nationally through the USDA Web Soil Survey, http://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm.
59 Burton, 2010; the bulk of the labor in gravity irrigation is through land-forming measures. After establishing the
system, water application can be automated.
60 Ali, 2011.
61 Ibid.
62 Guy Fipps, Irrigation Water Quality Standards and Salinity Management Strategies, Texas Cooperative Extension,
B-1667, 4-03, College Station, TX, https://www.extension.org/mediawiki/files/1/1e/Salinitydocument.pdf.
Congressional Research Service
25
c11173008
link to page 27 link to page 28 link to page 28 link to page 35 .
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
as the Clean Water Act.63 The Clean Water Act’s purpose is not to directly provide cleaner water
for irrigation, but agriculture is a beneficiary of these efforts.64
How much water is legally available to a farmer or an irrigation district is largely determined by
state water rights laws. Political, legal, and societal factors associated with water rights are not
discussed in detail in this report. For additional info, see CRS Report R43910, Water Resource
Issues in the 114th Congress.
Federal Assistance
The federal government provides agricultural producers with financial assistance, technical
assistance, research, and monitoring and reporting. A number of USDA agencies provide support
through education, outreach, and research. Also, federal funds are provided through conservation
programs to producers who adopt irrigation BMPs.
Financial Assistance
Financial assistance for irrigation BMPs adoption comes from farm bill conservation programs
like Environmental Quality Incentives Program (EQIP), Conservation Stewardship Program
(CSP), and Agricultural Management Assistance (AMA).65 These programs award funding or
technical support to qualified agricultural producers that implement conservation practices
according to predefined guidelines established by the program. Of the 17 irrigation BMPs funded
through farm bill programs (Table 3), nearly half ($564 million) of the $1.2 billion in funding
awarded between 2009 and 2014 went toward implementing sprinkler and microirrigation
systems. Figure 16 shows the majority of states receiving the highest amount of funding for
irrigation BMPs are in the West, with California ($187 million) and Texas ($151 million)
receiving the most funding.66 Three southeastern states are also in the top 10: Arkansas ($93
million), Mississippi ($60 million), and Louisiana ($34 million).
As previously discussed, increasing irrigation efficiency may also reduce groundwater recharge
and increase potential aquifer depletion. A recent study on groundwater use in the United States
found that the High Plains, Mississippi Embayment, and Central Valley aquifers are being
depleted at unsustainable rates. 67 These aquifers account for 93% of groundwater depletion that
occurred in the United States from 2000 to 2008.68 When looking at Figure 16, it is unclear if
irrigation BMP funding is helping to reduce groundwater depletion or exacerbating the problem.
63 33 U.S.C. §1251 et seq. (1972).
64 Water quality issues related to water used by agriculture for irrigation, as well as water resulting from irrigation are
not discussed in this report. For a more detailed analysis, including agricultural water-related concerns, see CRS Report
R43867, Water Quality Issues in the 114th Congress: An Overview.
65 For a more complete overview of USDA conservation programs, see CRS Report R40763, Agricultural
Conservation: A Guide to Programs.
66 For a state-by-state breakdown of EQIP irrigation BMPs funding, see Appendix C.
67 Landon Marston, Megan Konar, and Ximing Cai, et al., “Virtual Groundwater Transfers from Overexploited
Aquifers in the United States,” Proceedings of the National Academies of Science, vol. 112, no. 28 (July 14, 2015),
http://www.pnas.org/content/112/28/8561.full.pdf.
68 Ibid.
Congressional Research Service
26
c11173008
link to page 32 link to page 32 link to page 32 .
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Table 3. Farm Bill Irrigation BMP Funding by Practice, FY2009-FY2014
Cumulative funding over six-year time period in nominal dollars (in millions)
FY2009-
FY2009-
FY2014
FY2014
Practice Title
Funding
Practice Title (Cont ... )
Funding
10. Surface and Subsurface
1. Sprinkler Irrigation
$336.9
Irrigation
$14.6
2. Microirrigation
$227.4
11. Irrigation Ditch Lining
$10.8
3. Irrigation Pipeline
$167.4
12. Tailwater Recovery
$6.1
4. Pumping Plant
$123
13. Dam, Diversion
$1.6
5. Irrigation Land Leveling
$89.7
14. Irrigation Water Management
Plan (CAPS)
$1
6. Water Well
$70.7
15. Irrigation Field Ditch
$0.3
7. Structure for Water
Control
$68
16. Irrigation Canal or Lateral
$0.09
8. Irrigation Reservoir
$51
17. Transition from Irrigated to
Dryland Farming and Ranching
$0.002
9. Irrigation Water
$35
Management
Total
$1,203.8
Source: CRS from data supplied by USDA, NRCS on June 16, 2015.
Notes: Table includes data from EQIP, AMA, Agricultural Water Enhancement Program (AWEP), Wildlife
Habitat Incentives Program (WHIP), and Chesapeake Bay Watershed Initiative. Definitions and practice codes
for each practice can be found in Appendix B.
Environmental Quality Incentives Program (EQIP).69 EQIP awards financial and
technical assistance contracts for several irrigation BMPs with payments based
on estimated implementation costs. Conservation Activity Plans (CAPs) and
Conservation Innovation Grants (CIG) are also funded through EQIP. Irrigation
water management plans are funded through CAPs, while Conservation
Innovation Grants are used to fund projects like local or regional irrigation
conservation programs.70
Conservation Stewardship Program (CSP).71 CSP also provides funding for
irrigation BMPs, awarding payments based on conservation performance, as
opposed to flat payments based on rental rates or implementation costs. While
69 For a list of irrigation BMPs funded through EQIP along with their practice codes, see Appendix B.
70 For an example of how Conservation Innovation Grants are used to promote irrigation conservation, see Quenna
Terry, “Texas Water District, USDA Partner to Show Producers Way to Use Water Wisely,” USDA Blog (May 14,
2015), http://blogs.usda.gov/2015/05/14/texas-water-district-usda-partner-to-show-producers-way-to-use-water-wisely/
.
71 For a list of irrigation BMPs funded through CSP along with their practice codes, see Appendix B.
Congressional Research Service
27
c11173008
link to page 35 
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
CSP funds traditional conservation practices like crop rotation, it also funds the
implementation of precision technologies, including regional weather networks
for irrigation scheduling, irrigation system automation, and remote monitoring
notification of irrigation pumping plants.
Agricultural Management Assistance (AMA). AMA funds several of the same
irrigation BMPs that are funded by EQIP. Funding through AMA, however, is
limited to 16 states where participation in the Federal Crop Insurance program is
historically low.72
Figure 16. Farm Bill Irrigation BMPs Funding by Watershed, FY2009-FY2014
Cumulative funding over six years in nominal dollars
Source: CRS from data supplied by USDA-Natural Resource Conservation Service (NRCS) on June 16, 2015.
Notes: The map displays information by hydrologic unit code (HUC). Although some HUCs cross national
boundaries into Canada and Mexico, federal funding to producers implementing BMPs is for the United States
only. For a state-by-state breakdown of farm bil irrigation BMPs funding, see Appendix C.
Technical Assistance
Conservation Technical Assistance (CTA). CTA helps irrigators adopt
conservation plans by offering technical assistance through a national network of
locally-based conservationists. While CTA does not offer financial assistance, the
conservation plans developed through CTA can be used as a springboard to
72 Eligible states for AMA include Connecticut, Delaware, Hawaii, Maine, Maryland, Massachusetts, Nevada, New
Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Utah, Vermont, West Virginia, and Wyoming.
Congressional Research Service
28
c11173008
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
qualify for financial assistance programs. CTA is available to farmers and the
groups that support them, including state and local government units, citizen
groups, and professional consultants, and funded over $5.7 billion in technical
assistance between 2003 and 2013.73
Research
USDA provides information resources to irrigators through the Agricultural Research Service
(ARS), Economic Research Service (ERS), and National Institute of Food and Agriculture
(NIFA).
Agricultural Research Service (ARS). ARS is the primary agricultural research
organization in USDA and performs scientific research related to irrigation
BMPs. Recent ARS irrigation studies focused on improving irrigation
management, optimizing irrigation scheduling, and managing deficit irrigation.74
Economic Research Service (ERS). ERS is the primary source of economic
information in USDA and conducts economic and policy studies on agricultural
issues, including irrigation water use and conservation. Recent ERS studies have
looked at characteristics of irrigated farms in 17 western states and water
conservation trends in irrigated agriculture across the United States.75
National Institute of Food and Agriculture (NIFA). NIFA administers federal
funding to support agriculture related science and research, primarily at state
universities. NIFA-funded grant programs related to irrigation include the
Agriculture and Food Research Initiative (AFRI) Water for Agriculture Challenge
Area and the National Water Quality Program (NWQP).76
Monitoring/Reporting
Few irrigation-related monitoring and reporting efforts occur at the national level. The National
Agricultural Statistics Service (NASS) and U.S. Geological Survey (USGS) provide the most
complete national picture of irrigation water use but, due to differing methodologies and reporting
schedules, cannot be directly compared.
National Agricultural Statistics Service (NASS). NASS compiles data on the
United States agriculture industry through conducting surveys of producers.
NASS produces the Farm and Ranch Irrigation Survey every five years (i.e.,
2003, 2008, 2013), which serves as a national assessment of irrigated agriculture
in the United States.
United States Geological Survey (USGS). USGS, in the Department of the
Interior, produces an assessment of water use in the United States that is typically
73 USDA, NRCS, “CTA Cumulative Technical Assistance Funds FY 20013-2013,” (April 2014),
http://www.nrcs.usda.gov/Internet/FSE_MEDIA/stelprdb1251317.png.
74 A comprehensive list of ARS irrigation projects can be found by searching “irrigation” at http://www.ars.usda.gov/
research/projects.htm.
75 ERS products on irrigation can be accessed at http://www.ers.usda.gov/topics/farm-practices-management/irrigation-
water-use.aspx.
76 For more information on NIFA’s focus on water and water programs, see http://nifa.usda.gov/topic/water.
Congressional Research Service
29
c11173008
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
released every five years (i.e., 2000, 2005, 2010). This water use assessment
evaluates trends in major water use categories including irrigation.
Congressional Research Service
30
c11173008
.
Appendix A. Irrigation Technologies and Water Use
Figure A-1. Irrigation Technologies and Water Use by State, 2013
10
25
9
8
20
7
t
s
6
15
e
-Fee
cre
f Acr
o
5
f A
s
o
n
s
n
illio
M
4
10
illio
M
3
2
5
1
0
0
Sprinkler Irrigation
Microirrigation
Gravity Irrigation
Applied Irrigation Water
Source: CRS from USDA, NASS, 2013 Farm and Ranch Irrigation Survey, Tables 6 and 28, http://www.agcensus.usda.gov/Publications/2012/Online_Resources/
Farm_and_Ranch_Irrigation_Survey/.
CRS-31
c11173008
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Appendix B. Practice Codes and Definitions for
Irrigation BMPs77
Environmental Quality Incentives Program (EQIP). These irrigation practices
qualify for funding from the NRCS EQIP.
Sprinkler System—Code 442. A sprinkler system is a general term to describe the most common
types of pressure irrigation systems like center pivot, side roll, and linear move tower irrigation.
These systems spray water into the air through a sprinkler or nozzle over a crop area to provide
adequate soil moisture for crops. Sprinkler systems are also used for crop cooling, frost
protection, and dust control.
Irrigation System, Microirrigation—Code 441. Frequent low-pressure, low-volume irrigation
applied near the roots of the plant through above- or below-ground tubing.
Irrigation Pipeline—Code 430. A pipeline is built to convey water to an irrigation system or
storage area in a way that minimizes water loss.
Pumping Plant—Code 533. A pumping plant delivers water at a predefined pressure and flow rate
based on a conservation need and requires an on-site energy source.
Irrigation Land Leveling—Code 464. The reshaping of land based on an engineered plan to
increase surface irrigation efficiency, reduce erosion, prevent water logging of soil or crops, and
prevent water quality loss.
Water Well—Code 642. A water well is used to extract groundwater from an aquifer. Possible
interference with neighboring wells, groundwater overdraft, and impacts on cultural,
archaeological, or scientific resources near the site should be evaluated in planning.
Structure for Water Control—Code 587. A structure that is used to convey water, regulate
direction or flow rates, retain a specified water surface elevation, or measure water. These
structures include flashboard risers, check dams, division boxes, water measurement devices, and
pipe drop inlets.
Irrigation Reservoir—Code 436. A reservoir is a water storage structure that is built to provide a
reliable water supply for irrigation. Irrigation reservoirs may be built by constructing a dam,
embankment, pit, or tank.
Irrigation Water Management—Code 436. Planning efficient volume frequency and application
rate of irrigation to manage soil moisture and promote plant growth. Irrigation scheduling is the
most important element of water management.
Irrigation System, Surface and Subsurface—Code 443. An irrigation system involving earthwork,
multi-outlet pipelines, and water-control structures to convey water to irrigated areas while
reducing water loss, erosion, energy use, and water quality impairment.
Irrigation Ditch Lining—Code 428. A lining made of impervious material that is installed in a
canal, lateral, or ditch, to improve water conveyance, reduce water loss and energy costs, prevent
erosion, and maintain water quality.
77 Practice codes refer to an NRCS numbering system and are included for reference. For more detailed information on
each practice standard, refer to the conservation practice information sheet at http://www.nrcs.usda.gov/wps/portal/
nrcs/detailfull/national/technical/cp/ncps/?cid=nrcs143_026849.
Congressional Research Service
32
c11173008
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Irrigation System, Tailwater Recovery—Code 447. Facilities built to capture irrigation runoff that
can be conveyed back into the irrigation system for reuse to conserve water and improve off-site
water quality.
Dam, Diversion—Code 348. A diversion dam is constructed to divert surface water from a
watercourse or stream into another watercourse like an irrigation canal.
Irrigation Field Ditch—Code 388. A ditch built from earth materials to convey water from a
primary source to irrigation areas.
Irrigation Canal or Lateral—Code 320. A permanent channel created to efficiently deliver water
from water source to irrigation areas. The canal or lateral must be lined where soil is of
moderately rapid to very rapid permeability.
Irrigation Water Management Plan—Code 118. An irrigation water management plan is
implemented to achieve irrigation efficiency to optimize crop yield, reduce water contamination,
minimize soil erosion, manage soil salinity, and reduce energy use.
Transition from Irrigation to Dryland Farming and Ranching – Code 134. Dryland farming is a
method of production under limited precipitation in areas that are typically under severe resource
constraints. This method focuses on crop yield sustainability and water conservation.
Conservation Stewardship Program (CSP). These irrigation practices are
eligible for funding from the NRCS CSP.
Regional Weather Networks for Irrigation Scheduling—WQT07. Information from the regional
weather networks are used to track crop evapotranspiration to plan irrigation scheduling. By
combining this information with precipitation and soil moisture data, an accurate irrigation
schedule can be established.
Irrigation System Automation—WQT01. This type of system uses GPS-guided variable rate
irrigation or other similar technologies to adjust water application rates based on variable field
conditions like soil, topography, and crop type.
Irrigation Pumping Plant Evaluation—WQT03. This enhancement evaluates the energy
efficiency of a pumping plant and determines modifications that can reduce energy consumption
and water use.
Remote Monitoring Notification of Irrigation Pumping Plants—WQT05. A remote monitoring
notification system wirelessly transfers real-time information to the operator of a pumping plant
on any changes in the operating status of the irrigation system. This information is used to
prioritize field visits for required maintenance and adjustments.
Decrease Irrigation Water Quantity or Conversion to Nonirrigated Crop Production—WQT08.
This practice requires an irrigator to reduce or eliminate irrigation for the purpose of conserving
water supplies and reducing energy use where irrigation water is pumped.
Mulching for Moisture Conservation (Used in 2010 and 2011)—WQT02. This enhancement uses
fibrous mulch to reduce irrigation evaporation loss from the soil surface.
High-Level Irrigation Water Management—WQT09. High-level irrigation water management
reduces water and energy use through irrigation scheduling based on information acquired
through remote soil moisture sensors.
Center Pivot Irrigation System End Gun Removal—WQT10. This enhancement requires the
removal of an end gun sprinkler that is placed at the outer edge of a center pivot system to expand
Congressional Research Service
33
c11173008
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
irrigation coverage. This practice will improve water conservation and increase irrigation
efficiency.
Low Energy Precision Application Irrigation—WQT11. This enhancement converts standard
center pivot irrigation systems to low energy precision application (LEPA) irrigation systems.
LEPA systems apply water directly into furrows through nozzles placed close to the soil surface
to reduce evaporation losses and energy consumption.
Computerized Hole Selection for Poly-Pipe—WQT12. Computer software is used to optimize
hole sizes for poly-pipe used in furrow irrigation to decrease water quantity applied per season
and irrigation runoff.
Intermittent Flooding of Rice Fields—WQT13. This irrigation technique allows rice fields to “dry
down” to a saturated soil condition in between flooding cycles of rice fields.
Resource Conserving Crop Rotation (RRCR)—CCR99. This is a crop rotation that includes at
least one resource-conserving crop like a perennial grass to reduce erosion, improve soil fertility,
interfere with pest cycles, and reduce soil moisture depletion and water application.
Improved Resource Conserving Crop Rotation—CCR98. This is an enhancement of the Resource
Conserving Crop Rotation listed above to further reduce erosion, improve soil fertility, interfere
with pest cycles, and reduce soil moisture depletion and water application.
Congressional Research Service
34
c11173008
.
Appendix C. Irrigation BMPs Funding
Figure C-1. Farm Bill Irrigation BMPs Funding by State, FY2009-FY2014
Cumulative funding over six-year time period in nominal dollars
$200
$180
$160
$140
s
$120
llar
o
f D
o $100
s
n
illio
$80
M
$60
$40
$20
$0
Source: CRS from data supplied by USDA, NRCS on June 16, 2015.
CRS-35
c11173008
.
Irrigation in U.S. Agriculture: On-Farm Technologies and Best Management Practices
Author Contact Information
Peyton McGee
Megan Stubbs
Research Assistant
Specialist in Agricultural Conservation and Natural
pmcgee@crs.loc.gov, 7-1658
Resources Policy
mstubbs@crs.loc.gov, 7-8707
Acknowledgments
The authors appreciate the support and expertise of Nicole T. Carter, who contributed extensive peer
review of this report.
Congressional Research Service
36
c11173008