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<br />This proposed project will demonstrate new irrigation application technology and the economic benefits of <br />this technology to encourage irrigators to use more effective water management. This new technology is <br />low energy precision application (LEP A) through overhead center pivot systems and surge irrigation with <br />the use of computerized. solar powered valves. This technology combined with computerized irrigation <br />scheduling technology based on the use of solar-powered weather stations with cellular conununications <br />offers more effective methods of irrigation water use. More effective irrigation water use will help reduce <br />salt concentration by reducing evaporation from over-irrigation, excessive runoff and "perched" or high <br />water table areas. Salt pickup will also be reduced as runoff and deep percolation is reduced by more <br />effective irrigation water application. <br /> <br />An additional problem affecting water quality in the Arkansas River and its ground water aquifer is that <br />nitrates from highly fertilized crops are being carried to the river as tailwater return flow as well as through <br />the root zone and into the ground water aquifer by deep percolation. This is the result of over-irrigation due <br />to inefficient methods of water application and poorly timed irrigation. More efficient irrigation with LEP A <br />and surge irrigation combined with proper irrigation scheduling would help reduce these nitrate amounts. <br />"Fertigation" is a method of reducing nitrogen application by "spoon-feeding" the crops with small amounts <br />of nitrogen based on crop needs and is a very effective method of nitrogen application with both LEPA and <br />surge irrigation methods. "Fertigation" will be used on both the LEPA and surge irrigation demonstration <br />areas. <br /> <br />Alfalfa and other legumes and grasses and/or grass-legume mixtures will be part of the project to study other <br />possible practices to reduce salt and nitrate loading. As grasses have lower water and nitrate use than row <br />crops, the amounts of potential loading should be reduced. Also, alfalfa has a low nitrogen fertilizer <br />requirement and this should help reduce nitrate loading of the groundwater and runoff waters. <br /> <br />.. <br /> <br />As the cost of harvesting equipment continues to increase, a need to use livestock to harvest forage from <br />irrigated pasture is increasing. Many producers are re-evaluating livestock as a means of keeping harvest <br />cost down. But there is limited information on grazing irrigated pastures in the river valleys. Due to the <br />saline conditions that exist. more information is needed on grasses and/or legumes mixtures that will produce <br />the greatest return. <br /> <br />The economics of more effective irrigation management through new and improved technology and through <br />proper management of alternate crops will be important to the success of reducing salt and nitrate loading. <br />By reducing salt and nitrate loading with alternate crops such as grasses and legumes, water quality in the <br />river basins could be improved while increasing crop yields or decreasing damage. Many areas along the <br />Arkansas and South Platte rivers in Colorado and the Rio Grande River in Colorado and New Mexico could <br />utilize the irrigation technology and alternate crop management, provided results of the demonstration prove <br />economically sound. <br /> <br />Soil types and shallow water table conditions found on the demonstration site property are similar to those <br />found in river bottom areas in Colorado and New Mexico. Management problems of irrigated soils of this <br />type are greater due to the high clay content. Clayey soil is difficult to cultivate as it is cloddy when dry <br />and sticky and plastic when wet. These soils also have a low water-infiltration rate and the available water <br />holding capacity is high. Also. these soils are moderately to strongly affected by salts, partially due to the <br />shallow water tables. Salts tend to accumulate in soils that are not well drained. <br /> <br />The site selected for this proposed demonstration is the Stonewall Springs (Farm) located in Pueblo County <br />east of the'City' of Pueblo and divided by Hignway50'(Fig.I). The property is located. im'mediately north <br /> <br />7 <br />