4 January 2024

Optimizing crop combinations can alleviate water shortages


A study highlights how water scarcity can be solved in the U.S. six major river basins. Shifting to less water-intensive crops that still provide adequate incomes for farmers is crucial

by Matteo Cavallito


Crop replacement and the application of different agricultural strategies can reduce water consumption by more than 50 percent in the six major river basins that feed U.S. crop fields. This is supported by an article published in the journal Nature Water reporting the findings of a study conducted by the University of Delaware, the organization Sustainable Waters, and Virginia Tech.

The investigation, which covered the Great Salt Lake, lower Colorado River, Rio Grande, Snake River, Platte River and San Joaquin River, addresses a critically important issue as the impact of irrigated agriculture on water depletion. Today, according to a statement released by the researchers, irrigation absorbs 88 percent of all freshwater consumed on a global scale.

Agriculture and irrigation

“In the United States, the mismatch between irrigation demand and freshwater availability has been exacerbated in recent decades due to recurrent droughts, climate change and overextraction that dries rivers and depletes aquifers,” the study says.

However, “yet there has been no spatially detailed assessment of the potential for shifting to new crop mixes to reduce crop water demands and alleviate water shortage risks.”

The study was able to quantify river depletion, finding high to severe levels of irrigation scarcity in 30 percent of sub-basins in the western United States. In more than half of them, crops of livestock-feeding plants-such as alfalfa and other types of hay-are the largest consumers of water.

Water consumption can be reduced by 57 percent

In their study, researchers analyzed agricultural statistics to estimate farmers’ profitability with respect to different crops. In addition, the authors estimated the actual amount of water consumed by also processing climate and soil data. Finally, in proposing the ideal combinations, the scholars selected only those crops previously present in the observed areas.

“The crops that we suggested to replace the current crops being grown varies from area to area,” said Dongyang Wei, a researcher in the Department of Geography and Space Sciences at the University of Delaware involved in the study.

Substitute plants consume relatively less water but provide farmers with adequate income. Another important hydric-saving strategy is he use of fallowing, which involves leaving cropland fallow for one or more growing cycles. “To examine the opportunities for crop shifting and fallowing to realize further reductions in water consumption, we performed optimizations on realistic scenarios finding that additional water savings of 28–57% are possible across our study areas,” the study states.

New solution to hydric crisis

The authors, the statement says, now hope that the study will pave the way for a possible solution in managing the hydric crisis. A problem that has long been affecting regions in the western United States. In the future, the authors hope to conduct large-scale experiments by paying farmers to implement different crops and measuring the results from a hydrological perspective. This will make it possible to better assess the benefits of these solutions. Not only in America.

The findings, the research further notes, “demonstrate strong opportunities for economic, food security and environmental co-benefits in irrigated agriculture and provide both hope and direction to regions struggling with water scarcity around the world.”