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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 <br />in good condition are dominated by orchard grass, smooth brome, alfalfa and clover. Areas <br />that have poor drainage are dominated with rushes and sedges. Areas in less than good <br />conditions are dominated with Kentucky bluegrass and various weeds. <br />Morgan, Johnson and Benson all thought that they could achieve an annual production <br />potential of 3+ tons/acre in two cuttings as was asserted by operators in 1987 and reiterated in <br />1999. Since Johnson was the only person to both irrigate and harvest, his two first cutting fields <br />of 2.2 and 1.97 tons/acre are within the 1987 assumptions of area operators. These figures are <br />higher than those shown in table 2.04.10-8 which indicates an average 1932 Ibs/acre (.97 <br />tons/acre) in 1987. Variation in yield in 1999 was directly related to the degree of management <br />and climatic variability. The Alfafa field which was intensively managed produced the highest <br />yields (8523 Ibs/acre) while the least managed field that had been invaded by prarie dogs had <br />the lowest yield (1140 Ibs/acre) <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 <br />was warm and mild (table 2.04.10-2) and the precipitation for spring and summer has been <br />high (Table 2.04.10-1 ). Precipitation is running 177 percent of normal for the San Miguel Basin <br />(NRCS, 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 <br />phreatophytic vegetation. These situations occur where: 1) small natural drainages or swales <br />(with gentle slopes) collect tailwater drainage from the surrounding irrigated fields; 2) shallow <br />ground water, augmented by irrigation, daylights along exposed bedding planes or fractured <br />rock to form seeps and boggy areas; 3) shallow water conditions exist along the borders of <br />ponds and depressions in channels. Because of the variation in site specific water regimes <br />within the type, three components occur within the type: 1) Dense thickets of coyote willow <br />(REVISED 9/99) 2.04.10 - 65 <br />