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<br />C".> <br />00 <br />(f) <br />o <br />:-:-J <br /> <br />':..:: <br /> <br />The information on intake family, slope, soil, acreage etc. shown <br />on individual summaries in Appendix B was obtained from SCS files. <br />Other data were measured in the field or calculated. Data <br />collected is explained in detail under "Measurement and <br />Calculation" section of Appendix C. The advance time shown in <br />individual summaries is the time taken for water to advance from <br />the top (inflow measuring point) to the bottom of the field where <br />the outflow weir was located. The infiltrated depth was obtained <br />as the difference between measured flow (gross application) and the <br />measured runoff for irrigation event. <br /> <br />The precipitation and ETa data shown on Table 2 are measured from <br />planting date to harvest date. The amounts in these columns vary <br />for each site because of the length of record for different crops. <br />Some of the variations are due in part to the different crops and <br />climatic variations at each location. Among perennial crops, ETa <br />data vary for the same crop at different sites (e.g. sites 13 and <br />51) because of differences in crop cover and maturity. Stress <br />factors due to soil moisture deficit also affect ETa values (refer <br />to Appendix C for ETa definition) for both annual and perennial <br />crops. <br /> <br />Under individual irrigation summaries, the ETa and precipitation <br />data are shown in the tables as a value for each irrigation event. <br />The value shown is the calculated ET for the particular crop from <br />the time of previous irrigation event; or for the first irrigation <br />event it is ETa from the beginning of plant growth to the date of <br />the irrigation event. <br /> <br />The soil moisture deficit before irrigation was determined from the <br />daily water budget computer program. All sites were probed before <br />the start of the irrigation season to estimate soil moisture <br />deficit before irrigation. If the infiltrated depth for a <br />particular irrigation event exceeded the soil moisture deficit <br />before irrigation, then the soil profile is assumed to be full and <br />there is no soil moisture deficit after irrigation. However, any <br />excess beyond what is needed to fill up the soil profile is <br />considered to be deep percolation. <br /> <br />In 1990, the water budget program was updated to more accurately <br />estimate deep percolation for annual crops. In the past, deep <br />percolation for the first irrigation and or pre-irrigation was <br />considered to be any amount that was in excess of that required to <br />fill up the first foot of soil; the full root profile was not taken <br />into account. with this method, deep percolation estimates were <br />higher than what they should be. The updated program takes full <br />rooting profile into consideration. All previous data from 1986 to <br />1989 was re-processed using the updated program to get a better <br />estimate of deep percolation, soil moisture and ETa etc. <br /> <br />14 <br />