New MSU Map Initiative to Guide Irrigation Decisions
Irrigated agriculture is the largest consumer of freshwater globally, but precise records and maps of when and where water is applied by farmers are difficult to locate. Now a team of Michigan State University researchers has discovered how to track water used in agriculture.
In a paper published in the journal Geophysical Research Letters, the researchers detail their use of satellite images to produce annual maps of irrigation. The findings, the scientists said, will help farmers, water resource managers and others understand agricultural irrigation choices and make better water management decisions.
“We want to know how human activities are having an impact on the environment,” said hydrogeologist David Hyndman, professor and chair of the MSU Department of Earth and Environmental Sciences, and principal investigator of the project. “Irrigation nearly doubles crop yields and increases farmer incomes, but unsustainable water use for irrigation is resulting in depletion of groundwater aquifers around the world. The questions is, ‘How can we best use water?’”
The paper, “Annual Irrigation Dynamics in the U.S. Northern High Plains Derived from Landsat Satellite Data,” highlights the need to know when and where irrigation is occurring to help manage water resources.
By utilizing Google Earth Engine for modeling, the research team was able to leverage vast cloud computing resources to quantify how much irrigation usage changed from year to year—an important finding for farmers, crop consultants and policymakers to be able to improve the efficiency of irrigation. The team found that irrigated area roughly doubled from 2002 to 2016 in the research area.
The project focuses on an economically important agricultural region in the central U.S.—the Republican River Basin—which overlies portions of Colorado, Nebraska and Kansas, and provides surface water and groundwater irrigation over the High Plains Aquifer. The team found that irrigation in this area roughly doubled between 2002 and 2016.
Water use in this region can be complicated because it is regulated to preserve streamflow into Kansas in accordance with the Republican River Compact of 1942.
“Previously, we only knew what fields were equipped to irrigate, or total irrigated area per region, but we didn’t know which fields were irrigated in any particular year,” said Jillian Deines, MSU doctoral student and the paper’s lead author. “Our irrigation maps now provide this information for 18 years and can be used to understand what factors contribute to irrigation decisions.”
Google Earth Engine, a cloud-computing platform that makes large-scale satellite and environmental data analyses available to the public, has been an asset for computing a large number of satellite images.
“It’s exciting because it allows researchers like us to use consistent methodologies to examine large regions through time,” Deines said.
The project, co-authored by research associate Anthony Kendall, is supported by the joint National Science Foundation (NSF)–USDA National Institute of Food and Agriculture (NIFA) Water, Sustainability and Climate (WSC) program, and the joint NSF-NIFA Innovations at the Nexus of Food, Energy and Water Systems (INFEWS) program, and the National Aeronautics Space Administration’s graduate fellowship program.
“Knowing what to plant, how much land to plant, and how much irrigation water is necessary to support a crop through harvest has been a challenge for farmers throughout time,” said Tom Torgersen, NSF for WSC and INFEWS. “Farmers can now envision a future where models will provide options to help guide decisions for greater efficiency and crop productivity.”
USDA-NIFA, which also funded the project, said that the demand for agricultural products will increase in the future, while water for irrigation could decrease due to water quality concerns and competition.
“Key to the findings, Spartan researchers leveraged new computing power to handle the ‘big data’ of all available Landsat satellite scenes, to develop irrigation maps that help to explain past human decisions about irrigation water use and hold the promise for superior future predictability,” said Jim Dobrowolski, program officer for NIFA’s Division of Environmental Systems.
- via the College of Natural Science website
PHOTO (above): More than 9,000 Landsat images provide vegetation health metrics for the Republican River Basin, formed by the confluence of the North Fork Republican River and the Arikaree River just north of Haigler in Dundy County, Nebraska. Image courtesy of Jillian Deines.