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<br />c:::>. <br />."') <br />~.. <br />ct.) <br />"'1 <br />~ <br /> <br />of the secqnd 30 cm was used as an effective level of salinity. Where 9.7 cm <br />was applied (22 irrigations per year), a mean was taken between the top and <br />second 30 cm levels. At 7.3 cm and 29 irrigations a weighted mean of 2 IEc sur- <br />face.} +, L IEc sub) was t'aken. Where 35 irrigations of 6. T 'em were used, the Ec <br />3 <br /> <br />Table 4, Ratios of mean conductivity of saturated soil extract - mean conduc- <br />tivity of irrigation water, 1.41 mmho/cm, (Value encircled is that used <br />for median,) <br /> <br /> Holtvi lle <br /> Imperial Imperial <br /> Indio Meloland stratified complex <br />0-30 30-60 0-30 30-60 0-30 30-60 0-30 30-60 <br />cm cm cm cm cm cm cm cm <br />1.5 1.3 1.5 2.0 2. I 3.4 4.4 5.0 <br />1.7 t.~ 1.7 2.2 2.3 3.8 4.4 5.7 <br />Chil) C.LJI 1.8 2,3 2.7 3.9 4.4 dj) <br />1.9 1.8 1.9 2.4 2.9 44 '4'6) <br />c(i; ~.- <br />2.6 2.5 2.0 2.5 QJ) 4.8 6.2 <br /> '--'j '30\ 3.8 4.8 5.2 6.5 <br /> C-I,O_. \...,-~/ <br /> 2,3 3.4 3.9 5.4 <br /> 2.3 3.4 4.3 5.8 <br /> 2.3 3.7 <br /> 2.5 3.7 <br /> 3.4 5. I <br /> <br />of the top soil only was used. These values were estimated on the basis of <br />Henderson (1946) and Wadleigh (1948). An effective Ec was derived from the <br />above calculations by subtracting 2 mmho to adjust for the presence of significant <br />gypsum in both soil and water, The Ec in the sprinkler case was determined by <br />subtracting 1 mmho from the top soil and 2 mmho from the subsoil of table 7 <br />and calculating in the same manner as the soils above: Robinson (1969 ec), <br />Robinson et al. (1968), Robinson and Worker (1969). These data were developed <br />for the soils and Irrigation salinity levels shown in table 8. <br />Tables 9 through 20 were developed for each of the crops in tabe 6 at <br />acreages shown in table 5. Entering the corresponding salinity value from <br />table 8 into the declination yield curve from the California Committee of <br />Consultants (1974), a yield declination was obtained. This was multiplied by <br />the average yield of table 6 and then by the acreage of each of the"soil groups. <br />The amount of water for the 22-29-35 annual Irrlgatlons'was based upon <br />213 cm or 84 inches of water per year. For alfalfa this would occur as shown <br />In table 21. Other crops which are grown during only part of the year would <br />use the schedules as indicated in Guidelines (Staff Imperial County Extension <br />19 <br />