Determination of Economically Optimal Rate of Nitrogen Fertilizer for Irrigated Sunflower in Eastern Anatolia, Turkey

摘要

Fertilizer management is an important part of crop production. This is due in part to increasing costs for fertilizer materials, particularly nitrogen (N) fertilizer. Producers need to know how different production inputs affect crop yields so that they can choose technically efficient input combinations. They also need to know how input usage affects the profitability of their operations with varying input and crop prices. Fertilizer is an input that can easily be reduced, thus lowering input costs.However, fertilizer is a crop input that has a high return on investment if applied at appropriate levels. Prediction of optimum fertilizer rates is important because of increasing economic and environmental concerns. Optimum N rate is determined by fitting statistical models to yield data obtained from nitrogen fertilization studies. We used the three models (linear, quadratic and exponential models) to determine the optimum N rate in sunflower production in Erzurum, eastern Anatolia conditions, Turkey. According to the results of the study, the economic optimum N rate was found to be about 110 kg ha~(-1) for sunflower grown under irrigated conditions in the region.