Abstract:

The relationship between crop production and amount of evapotranspiration is very important to agronomists, engineers, economists, and water resources planners. These relationships are often determined using classical least square regression (LSR). However, one needs high amount of samples to determine probability distribution function. Linear regression also requires so many measurements to obtain the valid estimates of crop production function coefficients. In addition, deriving ET-yield regression for each crop and each district is usually expensive, since lysimetric experiments should be repeated for several years for each crop. The object of this study is to introduce a fuzzy linear regression as an alternative approach to statistical regression analysis in determining coefficients of ET- yield relations for each crop and each district with minimum data. The application of possibilistic regression has been examined with a case study. Two data set for winter wheat in Loss Plateau of China and North China Plain have been used. The current finding shows capability of possibilistic regression in estimation of crop yield in data shortage conditions.

Keywords: Data shortage; evapotranspiration; fuzzy regression; grain yield; production function.