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<br />eU0184 <br /> <br />. <br /> <br />(13) Mr. Walter Trimmer, University of Nebraska, Scottsbluff. Mr, <br /> <br /> <br />Trimmer is District Extension Irrigation Engineer and is largely responsible <br /> <br /> <br />for the irrigation scheduling portion of the AGNET system which is avail- <br /> <br /> <br />able to Nebraska farmers, <br /> <br />In the course of interviews with the above, it was recommended that <br /> <br /> <br />we also interview Kenneth Ververs (SCS, Loveland), William Kipper (SCS, <br /> <br /> <br />Julesburg) and Joseph Krib (SCS, Sterling), However, it was not possible <br /> <br />to coordinate our schedules and theirs, so these interviews did not take <br /> <br />place. <br /> <br />The interviewers arrived at several conclusions as a result of these <br /> <br />. <br /> <br />interviews, It is clear that there is no definitive literature on irri- <br /> <br /> <br />gation efficiencies in the study area. Many investigations have been made <br /> <br /> <br />in the past, and as a result of these some general trends are known. <br /> <br /> <br />A few recent studies were completed which included measurements of runoff <br /> <br /> <br />as well as deep seepage (through soil-moisture sampling), These were <br /> <br /> <br />limited in scope, however, and give only isolated data points, However, <br /> <br /> <br />as a result of these conversations, the following conclusions were reached <br /> <br />by the writers.!! <br /> <br />(1) The range of field irrigation efficiencies for the study area <br /> <br /> <br />varied from an average low of 20 to 40 percent to an average high of 75 <br /> <br /> <br />to 80 percent (surface irrigation). <br /> <br />(2) Field efficiencies will be higher when water availability is <br /> <br /> <br />low (i.e., ratio of requirement to delivery is high), <br /> <br />(3) Field efficiencies will be affected by soils, topography and <br /> <br /> <br />irrigation application depth in a manner which is generally known (see <br /> <br /> <br />efficiency calculations below), <br /> <br />(4) Farm ditch losses may vary greatly depending upon length, soil <br />and frequency of use. <br /> <br />(5) Field irrigation efficiencies for center-pivot systems in the <br /> <br /> <br />study area can range from an average low of 63 percent to an average high <br /> <br /> <br />of 83 percent, depending upon the level of management used (i,e., irrigation <br /> <br /> <br />scheduling). <br /> <br />. <br /> <br />!!The conclusions drawn are those of <br />pretation of interviewee remarks. <br />sions of the interviewees. <br /> <br />the writers, based upon their inter- <br />They are not necessarily the conclu- <br /> <br />-27- <br />