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An Overview of Irrigation Techniques & Technology
In areas where rain doesn’t come regularly or when growing water-hungry crops, farmers are forced to get creative. Irrigation uses groundwater, surface water, and water delivered directly to farms to hydrate thirsty plants.
Evapotranspiration and wind are issues farmers face when trying to get water to plants while avoiding waste. General access to water and a diminished supply are also struggles for farmers in many parts of the country.
While operations in western states make up the bulk of U.S. farms that irrigate, farms across the country use irrigation. Just five states – Nebraska, California, Texas, Arkansas, and Idaho – house 52% of the nation’s total irrigation acres.
There are multiple ways to irrigate. Research has backed numerous effective application strategies, but each farmer has their own preference and budget. On this page, you’ll find an overview of techniques and how irrigation fits into the U.S. agriculture landscape.
Drip Irrigation: Water to the Roots
One approach to getting plants the moisture they need is by sending water directly to the roots with a drip irrigation system or a subsurface drip irrigation system. A drip system is made up of hoses with holes throughout that pump water directly to plant roots within the soil. While this irrigation method is more expensive, farmers see a reduction in water applied. Drip can also be beneficial to oddly shaped or sloped fields.
Today, precision mobile drip irrigation (PMDI) exists, which is essentially a hybrid of drip and center pivot irrigation. PMDI uses drip hoses on a center pivot system, rather than nozzle heads, to get water to plants without getting wheel tracks wet or investing entirely in a drip system.
Center Pivot Irrigation
This method of irrigating involves long steel arms and sprinkler nozzles and pivots, usually electrically, around a center base to reach the entire field. In southwestern Kansas, farmers are getting innovative with their pivots to help reduce water usage without cutting yields to help the Ogallala Aquifer.
A farm family with 57 center pivot irrigation systems across central Kansas uses remote monitoring and control to keep up with all the units. When it comes to fertigation, the farmers manage injections themselves, but having remote control has helped the family dedicate more time to field scouting and nutrient management.
Irrigation Technology Advances
New technology is regularly revealed as environmental needs change and the U.S. takes a harder look at water consumption. Farmers already control their irrigation systems with full-color touchscreen displays, one of a number of advanced irrigation controller technology options. Apps are also available to maximize water use.
A University of Missouri smart app can advise Missouri farmers on when to irrigate. To help farmers do a better job of managing moisture, the app uses weather conditions based on field location, evapotranspiration estimates, and NRCS soil mapping and texture data.
Reporting Water Use
In the summer of 2012, Illinois struggled greatly with a lack of water. Farmers saw the direct hit as yields plummeted due to a dire need for moisture. One Illinois farmer yielded just 50 bushels per acre on one plot but harvested 190-bushel corn on a plot just 20 miles away that received .4 inches more rain. That farmer, along with many other Illinois producers, invested in an irrigation system to combat seasonal shortages after 2012.
Irrigation water application regulation has lots of room for improvement—particularly in Illinois. Only in 2015, when it became required, did Illinois farmers start reporting water use on irrigated land. The state has no water-use restrictions, no laws in place for future groundwater conflicts, and no restrictions on new system installations. Only half of the total use is actually reported, as of 2017.
Reducing Water Use
Drought and water shortages have farmers and consumers alike looking for ways to conserve the water supply. While some farmers are facing low aquifers and others have hard limits on what is allowed legally, water conservation is constantly being studied and implemented on United States operations.
In an effort to save water, University of Nebraska experts suggest adjusting levels based on soil type to keep the available soil water level above the 50% depletion level. When it comes to soybeans, moisture needs can differ vastly.
Fertigation and Chemigation
Irrigation systems are more than just water-delivery systems for plants. The advanced systems can also be a critical tool in farmers’ nutrient management plans. Fertigation injects fertilizers, soil amendments, and water soluble products into an irrigation system while chemigation injects chemicals. Today, farmers can use efficient variable-rate fertigation systems.
One Idaho farmer has been saving on fuel and avoiding driving on his crops with chemigation and fertigation for 37 years. His crops get 15 to 18 fertilizer applications and four to six chemical applications via his pivot systems each year.