Living in a world where we demand so much from the land and resources; it has become a priority to track and know two major pieces of our demand:
- How much?
- When we are using these resources?
Irrigation that is used for agriculture is the largest use of the fresh water supply around the world, but accurate records and maps of when and where water is applied by farmers are difficult to locate. Until a few years ago when a team of researchers has discovered how to track water used in agriculture.
In a 2017, paper that was published in the journal Geophysical Research Letters, the researchers detail their use of satellite images to produce yearly maps of irrigation without the world. The result that the scientists received will help farmers, water resource managers and others understand agricultural irrigation choices and in order to make better water management decisions.
They want to know how human activities are having an impact on the environment. And 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. Their main question was: “How can not only farmers best use water, but the worlds consumers as well?'”
The paper highlighted the need to know when and where irrigation is occurring to effectively manage water resources.
The project focuses on an economically important agricultural region of the central U.S. mainly the Republican River Basin which overlies portions of Colorado, Nebraska and Kansas, and provides surface water and groundwater to the High Plains Aquifer. The team found that irrigation in this area roughly doubled between 2002 and 2016. Which left them with the main question of why.
Water use in this region can be difficult because it is regulated to preserve stream flow into Kansas in accordance with the Republican River Compact of 1942.
From early research and knowledge, they knew what farms were equipped to irrigate, but not which fields were being irrigated during particular year, Jillian Deines the paper’s lead author mentioned. The irrigation maps provide this information over 18 years and can be used to understand the factors that contribute to irrigation decisions.
The researchers used Google Earth Engine, a cloud-computing platform that makes large-scale satellite and environmental data analyses available to the public, to quantify changes in irrigation from year to year an important finding for farmers, crop consultants and policymakers working to improve the efficiency of irrigation.
Google Earth Engine has been an asset for computing the large number of satellite images needed, the scientists said. It allows researchers to use consistent methods to examine large regions through time.
The project was 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.
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. Farmers can now envision a future where models will provide options to help guide decisions for greater efficiency and crop productivity.
Program managers at USDA-NIFA said that demand for agricultural products will likely increase in the future, while water for irrigation may decrease due to water quality issues and competitive uses.
The Republican River Basin researchers leveraged new computing power to handle the ‘Big Data’ of all available Landsat satellite scenes, and developed irrigation maps that help explain human decisions about irrigation water use, said Jim Dobrowolski which is a program officer in NIFA’s Division of Environmental Systems. The maps hold the promise of the ability to make future water use predictions.