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Green and growing
By Bruce Bosley Extension Agent/Cropping Systems, Colorado State University Cooperative Extension Irrigators who are dealing with forced cutbacks or, in some cases, total loss of applied water on fields can benefit from the experience gained by dryland farmers through changes they've made in their farming practices and crop rotation strategies. These farmers found that the traditional wheat fallow farming system is an inefficient user of annual precipitation in a region where water is the major limiting factor. Data collected in the Great Plains show that typically less than 25 percent of the precipitation received during the 14-month fallow period is stored in the soil. When little or no residue is left on the soil surface, water storage efficiency is less than 20 percent. Colorado and Nebraska research indicates that precipitation storage efficiencies of 40 to 60 percent are achieved when tillage is minimized or eliminated. The key to these improvements is maintaining crop residue on the soil surface and minimizing or eliminating soil disturbance. Unfortunately, little added wheat yield results from the additional water stored under no-till compared to mulch tillage systems. In fact, it costs more to save the additional water in a no-till system than the value of the added grain yield. Weed control with herbicides is more costly than with mechanical tillage. Water savings in no-till systems can be converted to profit only by switching to more intense cropping systems where fallow time is decreased and summer crops, like corn, grain sorghum, proso millet and annual forages are added to the rotation. Maximizing water storage, which permits more intensive rotations, requires residue on the soil surface to trap snow, absorb raindrop impact, slow runoff and minimize evaporation, as well as complete weed control at critical times in the production cycle. Northeast Colorado irrigation farmers can adapt the dryland farming systems developed by Colorado State University Extension researchers and hundreds of dryland farmers for their reduced and no irrigation fields. These have been shown to increase the precipitation use efficiency of the crops, improve soil, water and air quality while increasing net income. Colorado State University gives five necessary steps for farmers considering this profitable water saving method in the Fact Sheet: Dryland Cropping Systems, 0.516. These steps start with weed control due to their incredible ability to use up precipitation and stored soil moisture. Other steps include the possible crop rotations and how to sequence them, rotation fertility management, and overall system management. Irrigated farmers can also tap into the great wealth of experience held by their dryland farming neighbors. The Colorado Conservation Tillage Association is a collaboration of experienced farmers working with industry and University personnel who's goal is to spread research and on-farm gained information with others. Please contact me, Bruce Bosley about this or other cropping systems or natural resource topics at 522-3200, extension 285 in Sterling or 542-3540 in Fort Morgan. Date: 7/5/07
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