Irrigated Corn Boost Crop Energy Efficiency

With rising fuel prices and efforts to more efficiently utilize water for crop production, UNL Extension is working hard to help producers more effectively and efficiently use water resources while maintaining high crop yields. That's the theme of a recent portfolio of research by University of Nebraska agronomists Ken Cassman and Patricio Grassini. What's sometimes seen as an energy-hogging way to net huge corn yields can actually do so with high levels of efficiency and low impacts to the surrounding natural environment. The researchers say these are based on "several years' field data collected from a large number of commercial production fields in Nebraska" as well as other USDA data and farmer surveys.

Grassini says, irrigated corn had substantially larger net energy yield and less greenhouse gas emissions per unit of grain produced than corn from rainfed systems with much smaller input levels and lower yields. Crop's energy efficiency should be measured on a yield basis, not on land area used.
Converting irrigated land to dryland would yield a per-acre decrease in greenhouse gases. But, on the other side of the equation, it would require twice as many acres in production to raise the same amount of grain. Therefore, it is very important to convert irrigated agriculture back to dryland production for the sake of reducing greenhouse gas emissions.
Need to be pursued how the availability of resources like water can work together with a production system like center-pivot irrigation to maximize crop yields in water scarcity under a given production system.

The research of irrigated corn in Nebraska can be taken as a benchmark for other current and future irrigated cropping systems because it shows that achieving high energy efficiency, high crop yields, and low global warming potential are not mutually exclusive goals in commercial agriculture. 

Continued progress can come with use of best farm management practices, including rotation of corn with soybeans rather than continuous corn, use of conservation tillage practices rather than conventional disc-plowing, replacement of surface irrigation with pivot irrigation systems, and fine-tuning applications of nitrogen fertilizer and irrigation water.

If raising an irrigated corn crop is more efficient when it comes to natural resources, Irrigation obviously carries additional costs. If those resources are available, though, the difference in production is likely enough to eat up at least a large chunk of the additional expense of irrigation. Increase about 50-bushel-per-acre soybeans and 200-bushel corn with irrigation, will get uniform yields on the better clay-based ground.

Irrigated corn in Nebraska is highly efficient in the use of energy, water and fertilizer, say University of Nebraska-Lincoln scientists whose research found that increased yields more than offset the energy cost of these inputs.