Laserfiche WebLink
MEMORANDUM <br />December 13, 2013 <br />Issues with Selecting an Appropriate Crop Growth Stage Coefficient for the SCS Mod. Blaney <br />Page 8 of 34 <br /> <br />Location State Crop <br />Mandan ND Bromegrass <br />Davis CA Irrigated Pasture <br />Murrietta CA Irrigated Pasture <br />Merced CA Irrigated Pasture <br /> <br />AVG: <br />Table 6 - kc values for Bromegrass and <br /> <br />Lawn Grass / Kentucky Bluegrass. <br />grasses” suggests that they may be better represented as a “lawn” type grass <br />Kentucky Bluegrass as shown in Figure 3 <br /> <br />Figure 3 - kc vs. month for <br />grass” in Pasadena, CA <br /> <br />“Lawn grass” in Pasadena, CA and Kentucky Blu <br />“pasture grasses.” The Pochop data set was <br />elevation in Pasadena. A regression analysis of ARS 1275 data from Pasadena compared to SCS TR <br />21 showed a strong correlation (R2 = <br />lawn or Kentucky Bluegrass at or near an elevation of 864 feet above sea level. It seems reasonable to <br />assume that the SCS may have smoothed the SCS TR <br />Pasadena curve. <br />0.0 <br />0.2 <br />0.4 <br />0.6 <br />0.8 <br />1.0 <br />1.2 <br />0 10 20 30 40 50 60 70 80 90 <br />Cr <br />o <br />p <br /> <br />G <br />r <br />o <br />w <br />t <br />h <br /> <br />S <br />t <br />a <br />g <br />e <br /> <br />C <br />o <br />e <br />f <br />f <br />i <br />c <br />i <br />e <br />n <br />t <br />, <br /> <br />k <br />c <br />Issues with Selecting an Appropriate Crop Growth Stage Coefficient for the SCS Mod. Blaney-Criddle Eqn. <br />Elevation Month <br />(m) (ft) MAR APR MAY JUN JUL AUG SEP <br />502 1,647 0.89 1.09 1.21 1.21 1.16 0.72 <br />Irrigated Pasture 16 52 0.16 0.38 0.49 0.55 0.57 0.56 0.38 <br />Irrigated Pasture 334 1,096 0.30 0.64 0.86 0.88 0.83 0.79 0.76 <br />Irrigated Pasture 52 171 0.24 0.61 0.76 0.74 0.74 0.71 0.58 <br />226 742 0.24 0.64 0.81 0.85 0.84 0.81 0.62 <br />values for Bromegrass and “Irrigated Pasture” <br />Lawn Grass / Kentucky Bluegrass. A further investigation of SCS TR-21 coefficients for <br />may be better represented as a “lawn” type grass that is <br />Figure 3. <br />vs. month for ARS 1275 “pasture grasses,” SCS TR-21 “pasture grasses,” and “lawn <br />grass” in Pasadena, CA <br />awn grass” in Pasadena, CA and Kentucky Bluegrass from Pochop were compared to SCS TR <br />The Pochop data set was adjusted to reflect an elevation of 864 feet <br />A regression analysis of ARS 1275 data from Pasadena compared to SCS TR <br />= 0.929) as shown in Chart 2, which suggest that it closely r <br />near an elevation of 864 feet above sea level. It seems reasonable to <br />assume that the SCS may have smoothed the SCS TR-21 curve to eliminate the peaks and valleys of the <br />90 <br />10 <br />0 <br />11 <br />0 <br />12 <br />0 <br />13 <br />0 <br />14 <br />0 <br />15 <br />0 <br />16 <br />0 <br />17 <br />0 <br />18 <br />0 <br />19 <br />0 <br />20 <br />0 <br />21 <br />0 <br />22 <br />0 <br />23 <br />0 <br />24 <br />0 <br />25 <br />0 <br />26 <br />0 <br />27 <br />0 <br />28 <br />0 <br />29 <br />0 <br />30 <br />0 <br />31 <br />0 <br />32 <br />0 <br />33 <br />0 <br />Day of Year <br />Average of Irr. Pasture & Bromegrass <br />SCS TR-21 Pasture Grasses <br />Lawn Grass in Pasadena, CA <br />Criddle Eqn. <br />SEP OCT <br />0.72 0.54 <br />0.38 0.19 <br />0.76 0.65 <br />0.58 0.25 <br />0.62 0.41 <br />21 coefficients for “pasture <br />that is closely related to <br /> 21 “pasture grasses,” and “lawn <br />compared to SCS TR-21 for <br />864 feet, the approximate <br />A regression analysis of ARS 1275 data from Pasadena compared to SCS TR- <br />, which suggest that it closely represents <br />near an elevation of 864 feet above sea level. It seems reasonable to <br />21 curve to eliminate the peaks and valleys of the <br />33 <br />0 <br />34 <br />0 <br />35 <br />0 <br />36 <br />0