Relationships of cotton dry matter production and plant structural characteristics for wind erosion modeling

Annual soil losses from wind erosion in the United States are extensive. A means of predicting when and where these losses occur and the amount of the losses is vitally needed. Researchers with the U.S. Department of Agriculture's Agriculture Research Service are developing a Wind Erosion Prediction System (WEPS). WEPS will be made up of several submodels and various data bases. The CROP submodel of WEPS will calculate the total above-ground dry matter of a given crop at any given time after planting. Mathematical equations for the relationships of this total above-ground dry matter to leaf area, stem area, and plant height will be needed to calculate an erosion-reduction factor for use by WEPS. I developed such equations for cotton (Gossypium hirsutum L.) from data obtained in a 2-year growth and development study. The 1988 and 1989 growing seasons were wetter and drier than average, respectively, and the equation coefficients for the respective equations for the 2 years differed significantly, as indicated by their confidence limits. Consequently, the data for the 2 years were combined and additional equations developed for use in the WEPS model. These equations and other data presented may be of benefit to others for model building or testing.