Determination of an appropriate model for optimum use of N fertilizer in furrow irrigation

Abstract

Estimation of optimum fertilizer application is of interest because of production cost, environmental concerns, and performance increase. Optimum fertilizer rates can be determined by fitting statistical models to yield data collected from N fertilizer experi-ments. Quadratic polynomial, square root, Mitscherlich, hyperbolic trigonometry, quadratic polynomial threshold, and threshold linear models which describe the production function of sugar beet to different rates of N fertilization (0, 60, 120, 180 and 240 kg/ha) were evaluated with supplemental furrow irrigation in three replications in each of two years (2003 to 2004) of experiment. Economic, optimum N rates were estimated based on both fertilizer and crop costs in two years. The fertilizer rate was variable based on fertilizer cost to crop cost and also the applied model. Results showed that the quadratic polynomial model is the most appropriate model for describing the production function and optimal N application in sugar beet production. Using this model, the economic, optimum N rates in 2003 and 2004 were 235.8 and 248.9 kg/ha, respectively.

Keywords

• nitrogen fertilizer
• quadratic polynomial model
• economic consumption
• sugar beet