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2007 Soil and Water Conservation Society - Soil Quality Workshop
"Soil Quality: the Foundation for Natural Resource Quality"
DROUGHT MITIGATION AND SOIL QUALITY ENHANCEMENT WITH ALTERNATIVE DRYLAND ROTATIONS FOR THE CENTRAL GREAT PLAINS REGION
Drs. Merle F. Vigil, David Nielsen, Maysoon Mikha, Joe Benjamin, and Francisco Calderon
USDA-ARS, Akron, CO
Farmers in the dryland portion of the Central Great Plains Region (CGPR) make their living on land that receives 14-20 inches of precipitation annually. The evaporative demand in the region is between 4 and 7 times that amount and so the challenge to successfully farm the CGPR is great. The crops and land are nearly always in a water deficit. For ~70 years winter wheat-summer fallow (WF) has been the dominant dryland production system in the CGPR. With WF, the idea is to store precipitation in the soil during the 14-month “summer-fallow” period. That stored soil water is then available in the subsequent year to reduce the risk of crop failure (due to drought). The WF system, (which was a good idea 50 years ago) is for most soils in the region not economically or environmentally sustainable. Through the introduction of no-till and direct seeding, enough water is stored in the soil to justify increasing the cropping intensity from one crop in two years (as with WF) to 3 crops in four years (Wheat-Corn-Millet-Fallow) and in some cases to crop continuously (Wheat-Millet) with no summer fallow. In this presentation, we discuss results from no-till alternative crop rotation experiments at Akron and in the northern Great Plains. Analysis of the data from these experiments, show positive changes in farm-gate economics, crop yield, and soil quality when soils of the region are managed using no-tillage with intensive crop rotations. Also, these experiments, document increases in soil organic C, increases in aggregate stability, and improvements in soil water storage. Recently we have also documented additional yield enhancements in these no-till dryland systems by simply changing row spacing using a "skip-row technique."
Merle Vigil – Merle F. Vigil is a Research Leader/Soil Scientist for the USDA-ARS, Central Great Plains Research Station in Akron Colorado. His professional interests include: no-till dryland cropping systems in semi-arid agriculture; crop residue management and nutrient cycling of crop residues and organic amendments; fertilizer use efficiency particularly with N fertilizers in dryland rotations; precipitation storage efficiency and its effect on water and N use efficiency; mineralization-immobilization of soil organic N; crop residue N management strategies to maximize fertilizer and water use efficiencies; and simulation modeling of the above processes. He received a PhD in Soil Fertility/Soil Chemistry from Kansas State University in 1989, a MS in Soil Fertility from Colorado State University in 1983, and a BS in Agronomy (Crop Science) from Colorado State University in 1980.