How much water can be saved, or cash crop yield can be gained by continuous use of cover crops in West Central Nebraska cropping systems?

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Title: How much water can be saved, or cash crop yield can be gained by continuous use of cover crops in West Central Nebraska cropping systems?

Expected Outcomes: Cover Crop Clinic in West Central Nebraska. Establishment of mid to long-term cover crop rotation areas. Research and Extension publications on the possible water savings or cash crop yield gains due to continuous cover crop use in West Central Nebraska.

Problem description: Water use for agricultural purposes is limited in West Central Nebraska due to low annual rainfall (16-22 inches), areas with irrigation water allocations, and areas with sandy soils. Therefore, water savings are economically and environmentally relevant for farmers and the sustainability of the natural resources in the region. Besides the well-documented overall benefits of cover crops in other regions, their adoption in the West Central Region in dryland is rare and low in irrigated systems due to the concern of excessive water use by the cover crop that will compromise the following cash crop. These concerns are documented in previous small plot-type research while looking at different cover crop termination times. However, there is no mid to long-term research in West Central Nebraska on whether these one-year adverse effects of cover crops can be overcome in the mid or long-term by continuously using cover crops. This project aims to research the water use of continuous cover crops and cash crops in irrigated and dryland cropping systems in West Central Nebraska. Outcomes from this project are expected to provide guidelines on how much irrigation water can be saved when continuously using cover crops or how much cash crop yield can be gained by increasing soil water availability with cover crops in dryland, irrigated, and limited irrigation cropping systems of West Central Nebraska. 

Methodology: It is proposed a combination of experiments at research stations comparing continuous cover crop vs. no cover crop use under five levels of irrigation from 0 to 100% of crop evapotranspiration, farmers' participation through on-farm research trials, and incorporation of cover crop in dryland and irrigated long-term crop rotation (>10 years) already established. Using a neutron probe, we will track soil water. We will also quantify cash crop yield and cover crop biomass produced and compare results with the no-cover crop plots.

Quantify how many inches of water can be saved by continuous use of cover crops in irrigated cropping systems in West Central Nebraska.

Determine whether there is a rainfall or irrigation threshold at which cover crops' benefits disappear.

Establish mid to long-term experiments in irrigated and dryland systems to be used as showcases.

Recruit six farmers with a 3-year commitment for on-farm research and provide cover crop seed and guidelines to test cover crop water use in West Central Nebraska.

Develop a cover crops clinic for irrigated and dryland cropping systems in West Central Nebraska for crop consultants and farmers.