Laserfiche WebLink
<br />v. Description of Data and Software: South Platte Consumptive Use Model (SPCU) <br /> <br /> <br />2. USBR (United States Bureau of <br />Reclamation) - Precipitation estimation <br />method, based on U.S. Bureau of <br />Reclamation methodology, in which <br />effective rainfall is linearly related to <br />average monthly rainfall. <br /> <br />2.5.8 Soil and Crop Characteristics <br /> <br />Crop data determine the water-use <br />characteristics of crops during plant <br />development. These data include the earliest and <br />latest moisture use related to frost temperature, <br />water holding capacity, root depth, and <br /> <br />There are four basic soil types (clay, silt, sand, <br />and loam) and other soil types that are <br />combinations of the four (such as sandy loam or <br />sandy clay loam) can be added. The main <br />parameter that changes with soil type is the <br />Available Water Holding Capacity (A WC). A <br />value for A WC can be entered for each soil type <br />added. <br /> <br />Coefficients for crops determine the water-use <br />characteristics of crops. Crop coefficients, <br />typically referred to by the variable KC, <br /> <br />Completion Report: South Platte Mapping and Analysis Program <br /> <br />management allowable depletion. In addition, <br />planting and harvest dates can also be entered <br />(Figure 8). <br /> <br />There are three options that can be used for <br />determining the frost dates. A monthly mean <br />temperature from the weather data to determine <br />the frost dates. The second two methods use the <br />published 28 or 32 degree frost dates from the <br />weather station data selected for the area. Since <br />alfalfa is typically harvested more than once a <br />year, multiple dates can be specified for when <br />these cuttings take place. <br /> <br />..:ox <br /> <br />_. <br /> <br />)", O,:FiO$t ':)... <br />28 <br />45 <br />32 <br />32 <br />28 <br />32 <br />32 <br /> <br />150 <br />365 <br />137 <br />140 <br />184 <br />140 <br />140 <br /> <br />50 <br />45 <br />45 <br />55 <br />28 <br />55 <br />55 <br /> <br />Figure 8: Crop Characteristics Window <br /> <br />multiplied by reference ET, define the <br />consumptive use of a crop throughout a given <br />number of days called the period (Figure 9). <br />Different Kc values are used for the Blaney- <br />Criddle, Kimberly-Penman, and Penman- <br />Monteith. The planting and harvest dates for the <br />crop define the beginning and end of the period. <br />F or the Penman-Monteith method crop <br />coefficients can be based on Alfalfa or Grass <br />(Pasture) reference crops. <br /> <br />21 <br />