Variable Rate Application of Nitrogen Fertilizer in a commercial pear orchard

The application of high nitrogen (N) fertilization potentially leads to adverse environmental impacts due to nitrate leaching, ammonia volatilization, nitrous oxide (N 2 O) emissions and soil acidification. Determining the optimum amount of N fertilizer and minimizing the environmental impact is a difficult task, but it can be accomplished using Precision Agriculture techniques. Based on this concept of precision agriculture, site-specific management (SSM), rather than the traditional whole field approach, is considered as a practice that enables the farmer to manage field variability. The yield monitor and variable rate chemical application together with the adaptation of existing technologies (GIS, GPS) have made possible the application of SSM. In this study results of using variable rate application (VRA) in a pear orchard are presented. The application of Nitrogen fertilization was conducted using the method of VRA based on the Nitrogen loses of the yield of the previous year according to the literature. The experiment took place in a commercial pear orchard in the area of Tyrnavos (Larissa). Crop yield was monitored in both years before and after the VRA of fertilizer. The yield in the second year was not only increased in quantity (4 tons more) but also the production capacity of the trees with minimum production were improved (from 10,5 kg/tree into 20,5 kg/tree).