A module-specific post-processing calibration method to improve cotton yield mapping

Calibrating cotton yield monitor data is difficult, because there are many confounding factors, such as landscape, soil, ambient light and temperature, defoliation level, and variety that can cause sensor response to shift from field to field and even within a field. The conventional calibration method involves in situ weighing of basket loads, which is costly, logistically unfavorable, and not adequate to account for inconsistent performance of yield monitor sensors. In this work a module-specific post-processing method was used to calibrate cotton yield data. The method was enabled by a wireless communication and GPS based electronic system that can delineate the harvest location of each cotton module in the field during machine harvest. Module-specific correction coefficients were calculated as the ratio of module weight determined at the gin to the yield monitor based module weight integrated over the module harvest area. Module-specific lint turnout, also determined at the gin, was used to convert seed cotton yield to lint yield. The method was field tested on 16 cotton modules harvested from two study areas near College Station, TX. Results showed that yield monitor based weight deviated substantially from the actual weight for some modules, with errors ranging from −41.0% to +13.9%. Lint yield maps produced with module-specific post-processing calibration showed more reliable spatial patterns than maps produced with field-based post-processing. Combining the wireless communication and GPS system with the cotton yield monitor could greatly enhance the quality of cotton yield maps, making them more suitable for various precision agriculture applications.