A study has predicted the changes in the value of crop irrigation for corn and soybeans in the U.S. by the middle of the 21st century, displaying currently irrigated areas. Credit: Trevor Partridge et al.
An investigation into the pros and cons of enlarging irrigation systems for corn and soybeans considering future climate shifts has been conducted.
As global warming advances, the necessity to increase irrigation in the United States is essential to maintaining future crop yields, as drought is expected to worsen due to rising temperatures and changes in rainfall patterns. Currently, fewer than 20% of agricultural lands are designed for irrigation.
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Advantages of Increasing Irrigation
A study led by Dartmouth has discovered that by the mid-21st century, under moderate greenhouse gas emissions, the gains from enlarging irrigation will exceed the setup and running costs across an extended area of existing U.S. farmlands. The results indicate that rainfed corn and soybeans would benefit from irrigation in various states such as North Dakota, eastern South Dakota, western Minnesota, Wisconsin, and Michigan. Other states like Indiana, Illinois, Ohio, Kentucky, Kansas, and Oklahoma would also benefit from irrigation for soybeans. These results will be released on August 14 in Communications Earth & Environment.
Financial Considerations and Economic Study
Farmers may face significant costs, up to $160 per acre per year, for the installation and management of irrigation equipment. Trevor Partridge, a Mendenhall Postdoctoral Fellow and researcher with the U.S. Geological Survey Water Resources Mission Area, states that the study essentially maps out the future irrigation needs for corn and soybean crops.
Historically, areas like Nebraska, Kansas, and northern Texas have been heavily irrigated and provided high economic returns, but drought costs are driving farmers to invest in irrigation in the Corn Belt and southeastern U.S., with unpredictable long-term financial returns.
Analysis Approach and Climate Models
The research included running crop model simulations with various global climate projections, including hot, dry, cool, wet conditions relative to average projections, to analyze future growth under irrigated or rainfed conditions. Simulations were run for corn and soybeans, considering historical, mid-century, and end-of-century periods under different emission scenarios.
Economic Gains and Water Shortfall
The team explored where and when irrigation would make sense for corn and soybeans, considering water availability. The “irrigation water deficit” was calculated, measuring the difference between applied water and what should be available.
Findings and Water Supply
The findings reveal that by mid-century, enough water is likely available for soybeans in certain states but not for corn. Groundwater resources are abundant in some areas, yet benefits of irrigation are minimal in others.
“There is a mismatch between where there is enough water to irrigate crops without added strain on resources and where the investment in irrigation will be economically viable in the long run,” explains Partridge.
Environmental Challenges
Specific examples, such as the depletion of the Ogallala Aquifer, illustrate challenges. Increased irrigation may add stress to essential aquifers, depleting them faster than replenishment rates.
Implications for the Future
Higher warming levels could reduce the efficiency of irrigation, especially for corn. Soybeans may become more economically viable to irrigate due to their heat tolerance and lower water needs.
“By the century’s end, it may make more financial sense to irrigate soybeans rather than corn,” observes Winter. This could cause shifts in crop cultivation due to low-cost adaptation.
Complex factors such as yield performance, market values, energy costs, incentives, and weather forecasts must be considered in irrigation decisions. The study’s insights may aid agricultural and water resource management policies in adjusting to a warming climate.
Reference: “Irrigation benefits outweigh costs in more US croplands by mid-century,” 14 August 2023, Communications Earth & Environment. DOI: 10.1038/s43247-023-00889-0
Contributors to the study include Anthony Kendall and Bruno Basso at Michigan State University, Lisi Pei at Michigan State University and Georgia Institute of Technology, and David Hyndman at the University of Texas at Dallas.
Frequently Asked Questions (FAQs) about irrigation
What is the main focus of the study on Climate Change and U.S. Agriculture?
The study focuses on the cost-benefit analysis of expanded irrigation for corn and soybeans in the United States under future climate scenarios. It emphasizes that increasing irrigation is essential to sustain future crop yields, as drought conditions are likely to worsen due to climate change.
How will expanding irrigation benefit corn and soybeans by mid-century?
By the middle of the 21st century, the benefits of expanded irrigation for corn and soybeans are expected to outweigh the installation and operational costs in the U.S. The results show that areas currently relying on rain would benefit from irrigation, enhancing the growth of these crops in specific regions.
What are the economic considerations involved in expanding irrigation?
Expanding irrigation involves significant costs, including installation, maintenance, and operation, sometimes as much as $160 per acre per year. The study provides a U.S. map indicating where it will make the most economic sense to invest in irrigation for corn and soybean crops.
What are the environmental challenges related to increasing irrigation?
One significant challenge is the potential stress on key water resources, such as the Ogallala Aquifer, which might be depleted faster than it can be replenished. The study raises concerns about over-extraction and the sustainability of water resources for irrigation.
How does the study predict the future availability of water for irrigation?
The study examines water availability through calculations of the “irrigation water deficit” – the difference between applied water and what should be available. It concludes that there is relatively little overlap between where there is enough water and where the investment in irrigation will be economically viable long-term.
What are the future implications of the study regarding crop irrigation?
The study suggests that, with greater warming, irrigation may become more economically beneficial for soybeans than corn. It also emphasizes that the insights from the analysis can be used to aid agricultural and water resource management policies in adapting to a warmer climate.
More about irrigation
- Communications Earth & Environment
- U.S. Geological Survey Water Resources Mission Area
- U.S. Department of Agriculture National Agricultural Statistical Service
- Applied Hydroclimatology Group at Dartmouth
5 comments
I’m impressed by the detail in this study. Could this be a new era for farming in the midwest, with all this talk about expanding irrigation. But the environmental stress part has me concerned.
so they talk about switching from corn to soybeans but what about the market for these crops? is there a demand for more soybeans, if they’re going to make the switch. Makes me think.
This study’s quite interesting but I’m worried about the water resources in the long run. whats going to happen if we run out of water in key areas?
The cost to farmers is no joke, $160 an acre is significant. Where’s the support for small farms? It’s all about big agribusiness these days, isn’t it?
I think more focus should be on sustainable solutions and not just increasing irrigation. its like putting a bandaid on a bigger problem. But, I must admit the research seems thorough.