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<br />;, <br /> <br />TABLE 3 <br /> <br />ES TI MATES OF CONSUflPTI VE USE <br />OF WATER BY IRRIGATED CROPS <br /> <br />Crop <br /> <br />Rainfall <br />and Irrigation <br />(acre-feet per acre) <br /> <br />Alfalfa <br /> <br />2.5 <br /> <br />Grass, hay and pasture <br /> <br />2.2 <br /> <br />Corn and other annuals <br />(4 months season) <br /> <br />1.7 <br /> <br />From Table 2 it might be inferred that two acre-feet per acre <br /> <br />(3,3 AF minus 1.3 AF) of water would be salvaged by removing cottonwoods. <br /> <br />This, however, should be viewed as a short-term salvage since natural <br /> <br />processes would cause the regrowth of brush, grass, salt cedar and other <br /> <br />phreatophytes until, with time, the "pre-removal" condition is once more <br /> <br />established. Once this occurs, no real salvage is obtained. Thus, sal- <br /> <br />vaged water generated by phreatophyte removal is basically a temporary <br /> <br />measure with current technology. <br /> <br />PHREATOPHYTE CONTROL <br /> <br />Several methods of phreatophyte control ranging in cost from $3 per <br /> <br />acre to $100 per acre, have been examined in some detail, with differing <br /> <br />results. Al I have, come to a similar conclusion in that continuing phreato- <br /> <br />phyte control is rather expensive and troublesome,7 <br /> <br />Mechanical forms of phreatophyte control which have been investigated <br /> <br />include mowing, plowing, chopping, chaining, and raking. Typically, these <br /> <br />measures are effective for short times, but phreatophytes I'Ii II soon gro\" <br /> <br />back. The sal t cedar \.,i11 take root and ,thri ve even if only a small por- <br /> <br />tiOil of the branch I ies on moist soil, so in ,)11 mechanical clearing opera- <br /> <br />lions the Jebris must be disposed of in a:lcther place if r~'pid re9rO\vth is <br /> <br />to be avoided. <br />