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• Morgan plans a second cutting of alfalfa. Neither Johnson or Morgan plan a second cutting of <br />their grass hay and neither property owner remember previous years yields as both indicated <br />"they get what they get and stack it up°. <br />Composition of the irrigation hayland type is highly variable from field to field. Fields generally in <br />good condition are dominated by orchard grass, smooth brome, alfalfa and clover. Areas that <br />have poor drainage are dominated with rushes and sedges. Areas in less than good conditions <br />are dominated with Kentucky bluegrass and various weeds. <br />Morgan, Johnson and Benson all thought that they could achieve an annual production potential of <br />3+ tons/acre in two cuttings as was asserted by operators in 1987 and reiterated in 1999. Since <br />Johnson was the only person to both irrigate and harvest, his two first cutting fields of 2.2 and <br />1.97 tonslacre are within the 1987 assumptions of area operators. These figures are higher than <br />those shown in table 2.04.10-8 which indicates an average 1932 Ibs/acre (.97 tons/acre) in 1987. <br />Variation in yield in 1999 was directly related to the degree of management and climatic variability. <br />The Alfafa field which was intensively managed produced the highest yields (8523 Ibs/acre) while <br />• the least managed field that had been invaded by prarie dogs had the lowest yield (1140 Ibslacre). <br />A dominant factor contributing to production values in 1999 is the climatic trend for 1998-1999. <br />1999 is thus far proving to be an excellent year for herbage production. The 1998-1999 winter was <br />warm and mild (table 2.04.10-2) and the precipitation for spring and summer has been high (Table <br />2.04.10-1). Precipitation is running 177 percent of normal for the San Miguel Basin (NRCS, <br />NOAA). This trend has had the effect of elevating production levels. <br />Swale/Drainge Tvae. Flood irrigation of lands on and adjacent to the study area, has created <br />water regimes in certain locations that favor the establishment of hydrophytic and phreatophytic <br />vegetation. These situations occur where: 1) small natural drainages or swales (with gentle <br />slopes) collect tailwater drainage from the surrounding irrigated fields; 2) shallow ground water, <br />augmented by irrigation, daylights along exposed bedding planes or fractured rock to form seeps <br />and boggy areas; 3) shallow water conditions exist along the borders of ponds and depressions in <br />channels. Because of the variation in site specific water regimes within the type, three <br />components occur within the type: 1) Dense thickets of coyote willow (Salix exioua) which occur <br />primarily adjacent to the west lateral CC Ditch. 2) Less well-drained areas, or areas where <br />• (REVISED 8/15/00) 2.04.10 - 58 <br />