Agricultural water use has become a complex issue around the
world.
Water is the main input needed for crop production; yet, in many regions, water
from precipitation is not sufficient or does not occur at the right time for
optimum plant growth or crop yield.
In the United States, nearly 56 million crop acres — or about 25 percent of
all farmland — are irrigated, according to the USDA’s 2018
census.
Globally, irrigated agriculture represents about 20 percent of total cultivated
land.
The growing awareness to conserve water has stimulated
innovation
around the world.
Farmers,
nonprofits,
engineers,
companies
and organizations are using a host of strategies and technologies to produce
crops with less water:
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A wastewater treatment plant in Reggio Emilia, Italy, supplies purified
wastewater to irrigate about 5,000 acres of crops via canals — which
conserves surface water and groundwater for other uses. The system offers
traceability, real-time water flow rates and other data.
-
Heavily subsidized electricity and solar pumps for irrigation have depleted
groundwater in parts of India. A government program in Karnataka
State now requires local electrical companies to buy back surplus solar
power from farmers. Treating solar power as a cash crop to power irrigation
adds an economic incentive for farmers. According to Tushaar Shah, an
International Water Management Institute senior fellow based in India,
“Solar pumps can unlock India’s energy-irrigation logjam — and [in] other
parts of South Asia, as well — if the right incentives are made to farmers
to manage groundwater resources sustainably.”
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Even smaller farming operations are finding opportunities to manage
irrigation and the quality of water leaving their fields. Tim Scates’
soybean
farm
in southern Illinois irrigates 35 to 40 percent of its acres each year
with technology that mimics ideal raindrops — large enough not to evaporate,
but small and slow enough to not compact the soil — using varying nozzle
sizes, water pressures and spray patterns. Scates uses calculations from
solar-powered soil moisture probes to decide when and how much to irrigate
for maximum return on investment. “We don’t want to waste any water — or the
energy it takes to pump it,” Scates says.
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The Niger Basin Authority aims to make the Niger Basin, which reaches
parts of nine countries, a space for sustainable development through water
resource management by 2025. The plan includes irrigation and food-security
projects such as water storage for a joint irrigation and fish culture
program, and infrastructure rehabilitation.
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The Land Institute in Salina, Kansas develops perennial alternatives
to food crops.
Kernza
— which can be used in place of wheat to make beer and pasta — is bred from
a forage wheatgrass. It uses less water and allows more soil carbon
sequestration.
-
The System of Rice Intensification (SRI) — developed in the 1980s in
Madagascar — increases irrigated rice productivity with soil, water and
nutrient-management practices. SRI methods increase yields 20 to 50 percent,
while reducing irrigation water use by 30 percent to 50 percent, compared
with conventional systems.
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A Chilean engineer developed a system that turns wastewater into clean
water in just four hours using earthworms and microbes. The earthworms feed
on waste, breaking down nutrients and potential contaminants. Layers of
sawdust, wood shavings, and gravel or rocks remove solids. Both layers
contain bacteria that further break down organic material, leaving clean
water to be chlorinated for safety.
-
In the Murray-Darling Basin — Australia’s most complex river system
— water can be bought and sold based on supply and demand. Water users
participate in regulated markets to purchase water to meet their needs,
which encourages water use efficiency and protects availability. These
markets are a vital business tool for farmers and producers.
The Illinois Soybean Association and other
agricultural groups support the work of Field to Market: The Alliance for
Sustainable Agriculture, which measures the environmental footprint of
agriculture that is outcome-based, science-based and technology-neutral.
Field to Market released its first National Indicators Report in 2009. The
sustainability indicators include energy and land use, greenhouse gas emissions,
soil carbon, soil conservation, irrigated water
use
and water quality.
By incorporating new technologies and tactics into farming practices,
agriculture can promote more efficient irrigation and water management — and
play a major role in global water conservation and reuse.
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Illinois Soybean Association
Published Nov 5, 2020 6am EST / 3am PST / 11am GMT / 12pm CET