WSP10412 - Laserfiche WebLink

Home Browse Search

nD:187 . Davlioht Percentaoes As in the case of CRSS, CU&L Reports used the monthly daylight percentage values, which vary according to latitude, obtained from tables in SCS Technical Release No. 21. Irrioation Water Reauirements. The percentages were linearly adjusted for the partial months at the beginning and end of the growing season. Croo Growth Staae Coefficients Values for K, a coefficient reflecting the growth stage of a particular crop, were obtained from the curves supplied in SCS Technical Release No, 21. lrrioation Water Reauirements, Effective Rainfall The SCS effective rainfall method as explained in SCS Technical Release No. 21, Irrioation Water Reauirements was used with a 3-inch application depth. Growino Season . All of the growing season limits suggested lrriaation Water Reauirements, were used. and pasture as documented below. For the 1971-75 CU&L Report, beginning and ending growth dates appear to be a combination of a mean temperature for initiation of growth in the spring and frost dates to end the growing season. Pasture and alfalfa seasons ended at a temperature equivalent to the 28 of frost in the fall. in SCS Technical Release No. 21. Exceptions were made for alfalfa The 1976-80 CU&L Report made a minor change the growing season for pasture. Rather than the 280F frost, a mean temperature of 4SoF was used to end the growing season of pasture, The.ending temperature of 4SoF for report and the 1986-90 CU&L data, based on the recommended beginning temperature of 4SoF. 80th reports dates for all other crops. pasture was also used for the 1981-85 CU&L Alfalfa's growing season was developed mean temperature of SOoF to the ending mean used the same fixed planting and harvest Frost Data A date was set for crops where the growing season ended at a temperature equivalent to a 320F or 28'F frost in the fall. Generally, the normal date on which frost occurred was considered the harvest date. . Consumptive use development for 1986-90 incorporated the 50 percentile date for the 280F fall frost as the end for alfalfa's growth. This 50 percentile dates were found in the Climatoloov of the U.S. No. 20. Suoolement No.1, Freeze/Frost Data. 1988.