Laserfiche WebLink
<br />LEP A and/or surge irrigation combined with computerized irrigation scheduling technology, based on the use of <br />atmometers and weather data pods to determine evapotranspiration, is a more effective method of irrigation water <br />use. More effective irrigation water use will help reduce salt concentration by reducing evaporation from over- <br />irrigation, excessive runoff and "perched" or high water table areas. Salt pickup will also be reduced as runoff and <br />deep percolation is reduced by more effective irrigation water application. <br /> <br />. <br /> <br />Cropping patterns and the use of value added crops will be demonstrated to help maintain the economic viability <br />of the area. Over the two year period of the study, salt tolerant crops will be planted and compared to alfalfa, com <br />and other crops presently grown in the area. These crops include legumes, sorghum sudangrasses and other forage <br />crops. <br /> <br />The economics of more effective irrigation. management through improved technology and through proper <br />management of alternate crops will be important to the success of reducing salt loading. By reducing salt loading <br />with salt tolerant crops such as grasses and legumes, water quality in the river basins coul4 be improved while <br />increasing crop yields or decreasing damage. <br /> <br />"Perched" water table areas have been created by over-irrigation in several areas east ofJohn Martin Reservoir and <br />has caused excessive salting of these soils. An existing drain ditch will be cleaned to its original depth and the <br />effect of this cleaning will be observed using a trunk-mounted auger and/or by the use of shallow observation wells. <br />A tile drain will be installed in cooperation with the NRCS and water levels will also be observed at this location. <br />Crop yield and/or the ability to grow crops on an adjacent area will also be observed and measured when possible. <br /> <br />The quality of the water being used on each of the demonstration sites will be tested for irrigation suitability. <br />Nitrates, phosphates, salinity and sediment load will be determined on both irrigation and runoffwaters. <br /> <br />II. Methods and Evaluation Procedures <br /> <br />The demonstration areas will be re-mapped for soil type in the fall and/or winter of 1999/2000 by the NRCS. <br />Salinity mapping will be done during the demonstration period when arrangements can be made for the equipment. <br />Soils remapping will be done to give more detailed information for the project. Crops will be planted the fall of <br />1999 or spring of2000 or will be existing crops such as alfalfa or pasture grass. <br /> <br />Soil tests will be taken before and after growing season to determine nutrient needs and use. Sub-surface nitrogen <br />and salinity will be determined by sampling from the two-foot level. <br /> <br />Water quality samples will be taken from the water sources on the demonstration sites under the center pivot <br />systems and the surge irrigation system throughout the growing season. A complete irrigation water suitability <br />analysis will be conducted on these samples and will include conductivity, total dissolved solids (IDS), salts, <br />nitrate-nitrogen and phosphate. <br /> <br />Surge furrow irrigation and conventional furrow irrigation will be compared as to irrigation and runoff amounts, <br />nitrate, phosphate and salt loading, water quality, and yields and returns from the two furrow irrigation methods. <br /> <br />Irrigation scheduling will be determined by use of CROP FLEX, an Irrigation Scheduling Program developed by <br />Colorado State University. Weather information will be obtained from data pods and atmometers located near or <br />at demonstration sites. <br /> <br />2 <br />