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MEMORANDUM <br />December 13, 2013 <br />Issues with Selecting an Appropriate Crop Growth Stage Coefficient for the SCS Mod. Blaney-Criddle Eqn. <br />Page 19 of 34 <br /> <br />SCS TR-21 coefficients should not be taken at face value and judgment should be applied when they are <br />relied upon. <br /> <br />Crop <br />[1] <br />Referenced <br />Source for kc <br />[2] <br />Confidence <br />Level (R2) <br />[3] <br />Elev. that kc <br />may represent <br />[4] <br />Adjustment <br />Required? <br />[5] <br />Adjustment <br />Amount <br />[6] <br />“Pasture Grass” <br /> Bromegrass <br /> “Irr. Pasture” <br /> <br />ARS 1275 <br />ARS 1275 <br /> <br />N/A <br />N/A <br /> <br />1,647’ <br />440’ <br /> <br />Yes <br />Yes <br /> <br />9.4%, 7.6% <br />9.4%, 7.6% <br />Lawn / KY Bluegrass * <br />Pochop (1984) <br />SCS TR-21 “pasture grasses” <br />ARS 1275 <br />- <br />0.929 <br />- <br />4,428’ <br />0’ <br />864’ <br />Yes <br />Yes <br />Yes <br /> <br />9.4%, 7.6% <br /> <br />Sugar Beets ** SCS TR-21 <br />ARS 1275 <br />0.930 <br />0.928 <br />3,188’ <br />4,534’ <br />No <br />Yes <br />N/A <br />10% <br />Corn, grain SCS TR-21 0.980 N/A N/A N/A <br />Alfalfa <br /> Clover <br /> Alfalfa-Grass <br />SCS TR-21 <br />ARS 1275 <br />ARS 1275 <br />0.946 <br />- <br />- <br />1,442’ <br />1,521’ <br />2,375’ <br />Yes <br />Yes <br />Yes <br />6.4%, 9.1% <br />6.4%, 9.1% <br />6.4%, 9.1% <br />Small Vegetables SCS TR-21 0.953 13’ Yes 10% <br />Dry Beans <br /> Small White Beans <br />SCS TR-21 <br />ARS 1275 <br />0.802 <br />N/A <br />N/A <br />49’ N/A <br />Yes <br />N/A <br />10% <br />Sorghum SCS TR-21 0.851 2,404’ Yes 10% <br />Wheat SCS TR-21 <br />ARS 1275 <br />0.373 <br />N/A <br />N/A <br />varied N/A <br />varied N/A <br />10% <br />Small Grains <br /> Barley <br />SCS TR-21 <br />ARS 1275 <br />0.860 <br />NA 3,091’ Yes 10% <br />Orchard <br /> with cover26 <br /> no cover27 <br /> <br />SCS TR-21 <br />SCS TR-21 <br /> <br />0.998 <br />0.991 <br /> <br />- <br />441’ <br />- - <br />Table 15 – Sources of kc for use in SCS modified Blaney-Criddle equation. <br /> <br /> * Refer to Table 3; ** Refer to Table 6 <br /> <br /> [1] Crop type <br /> [2] Referenced source of kc for crop in [1] <br /> [3] Level of probability that the crop presented in [1] is represented by the reference source in [2] <br /> [4] Elevation that kc was developed at (or may represent) <br /> [5] Elevation adjustment required below 6,400 feet in elevation above sea level <br /> [6] Recommended elevation adjustment amount. Refer to Table 1 <br /> <br /> <br /> <br /> <br /> <br />26 Data references “deciduous fruit” during the peak of the year and lemons, grapefruit, and oranges in California and Arizona for the <br />shoulder months <br />27 Data references “deciduous fruit” and walnuts in California