Title: Crop Growth Modeling in the Wind Erosion Prediction System Author
Submitted to: ASABE Annual International Meeting
Publication Type: Abstract Only
Publication Acceptance Date: November 1, 2007
Publication Date: N/A
Technical Abstract: On land used for the production of food and fiber, the amount of growing crop and crop residue remaining on the field during no growth periods often determine whether the field is susceptible to the erosion of the soil by wind. The crop growth sub-model component of the Wind Erosion Prediction System (WEPS) was designed to reflect the growth patterns of annuals, winter annuals, bi-annuals and perennials on different soils, in varying climates, and under different management practices. Wind erosion simulation requires that the model capture the annual variability of biomass accumulation for non-irrigated crops. Initial growth is simulated by distributing energy from seed biomass into initial root, stem and leaf biomass. From this initial leaf area, photosynthetic biomass production is partitioned into fibrous root, storage root, stem, leaf and reproductive biomass stores. Partitioning fractions are a function of accumulated crop specific heat units. Leaf biomass is divided into living and dead fractions to account for senescence and freeze kill. Reproductive biomass is divided into grain and chaff fractions. Photosynthetic biomass production is based on net radiation, living leaf area, the canopy geometry and density, water and temperature stress. Re-growth after harvest or freeze damage is triggered by the loss of living leaf area. Necessary conditions are warm temperatures, the availability of storage biomass, and no tuber dormancy. Nutrient stress is not considered. Methods are also included to match yields and average yield residue ratios used by NRCS in RUSLE2. The accumulated biomass and geometric descriptions of the crop are used to calculate drag coefficients, interception of moving soil particles, surface sheltering and evaporation reductions in other sub-models. Examples of model performance under different management practices and diverse climate locations are presented.