Submitted to: International Conference on Precision Agriculture Abstracts & Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 7/20/1998
Publication Date: N/A
Interpretive Summary: Precision agriculture or site-specific management is a management strategy in which cropping inputs such as fertilizers are applied at varying rates across a field in accordance with local crop needs. This management strategy requires a good understanding of the factors limiting yield so that appropriate actions can be taken to optimize yields. Analysis of the yield limiting factors at each point in the field is complex. Statistical techniques have been used but they lack the ability to analyze the temporal effects of important factors such as weather. The use of crop simulation models allows the user to include weather factors and to evaluate the effect of alternative scenarios on crop development and yield. In this project, the ability of an existing crop growth model, CERES-Maize, to simulate the yield variations measured during the 1997 cropping season in a field located in central Missouri was evaluated. The initial results show that models have good potential to become an important tool in precision agriculture. The results of this work will benefit the scientists developing models by providing them with information on how to improve the models for use in precision agriculture. Producers and crop consultants will also benefit by having additional tools available to analyze management practices and improve their decision making process.
Technical Abstract: Crop simulation models have been used historically to predict average field crop development and yield under alternative management and weather scenarios. The objective of this project was to evaluate and test a new version of the CERES-Maize model that was modified to improve the simulation of site-specific crop development and yield. Seven sites within na field located in central Missouri were selected based on landscape position, elevation, depth to the claypan horizon and past yield history. Detailed monitoring of crop development and soil moisture during the 1997 season provided data for calibration and evaluation of the model performance at each site. Mid-season water stress caused a large variation in the measured yield with values ranging from 3.0 Mg/ha in the eroded side-slope areas to 11.7 Mg/ha in the deeper soils located in the low areas of the field. Results showed that model modifications improved its ability yto simulate site-specific crop development. Areas of potential model improvement and further investigation were discussed.