Generating a digital management map for variable rate herbicide application using the global positioning system

摘要

This study was conducted to generate a Digital Management Map (DMM) for Variable Rate Application (VRA) of Cyanazine pre-emergence herbicide using the Global Positioning System (GPS). The main objective of this study was to develop a precision method of herbicide application which eventuates to save herbicide and reduce its adverse effects on the environment and agricultural products. Around 6500 m2 uncultivated field was selected and local and Universal Transverse Mercator (UTM) coordinates of the field were determined using Total Station surveying equipments and four static GPS receivers. Data processing was performed using a Personal Computer (PC) equipped with COMPASS software. By means of LAND software a 42-cell grid was created and laid out on the selected field. Then, soil samples were taken at the center of each cell, and texture and organic matter content (OMC) of each soil sample was determined. Using Kriging interpolation method, soil texture and soil OMC values were determined at other grid points. By considering manufacture recommendations for herbicide application based on soil OMC and soil texture, four management zones with four different herbicide application rates as 1.4, 1.7, 2.9 and 3.5 L ha-1 were determined and eventually a DMM was generated. Using the generated DMM and VRA, total required herbicide for the selected field was determined to be 1.61 L and it was concluded that herbicide application can be decreased up to 13% in compared with a uniform herbicide application rate for the entire selected field.