Submitted to: International Symposium on Precision Agriculture
Publication Type: Abstract Only
Publication Acceptance Date: July 3, 2002
Publication Date: July 14, 2002
Citation: Gish, T., Buss, P., Daughtry, C.S.T., Dulaney, W.P., Walthall, C. 2002. Estimating corn grain yeild from temporal variations of soil moisture. In: Proceedings of 6th International Conference on Precision Agriculture and Other Precision Resource Mnagement Conference, July 14-17, 2002, Bloomington, Minnesota. p. 157. Technical Abstract: Soil moisture is often sited as the principal factor controlling yield response in rain-fed agricultural production systems. During the past two decades, a great deal of research has been conducted that attempts to describe the spatial and temporal variability of crop yield as a function of soil properties and landscape position. In general, soil moisture readings are found to be weakly correlated with yield (coefficients of determination are frequently < 0.4 ) in part because they do not provide any information on the temporal variation of plant available water. A 20 ha research site located at the USDA-ARS Beltsville Agricultural Research Center, Maryland, has been used to evaluate the spatial distribution of corn (Zea mays L.) yield under a variety of climatic conditions using real-time soil moisture observations. Three growing seasons characterized by a mild drought, a severe drought, and near optimum rainfall conditions were investigated. The temporal patterns of over 36,000 soil moisture observations a day were used to evaluate the onset of plant stress induced by either too little or too much water. A protocol was developed, based solely on soil moisture measurements, which was highly correlated (coefficient of determination, 0.88) with corn grain yield over the three year period. These results support the concept that a knowledge of soil water dynamics is critical to understanding and managing the spatial and temporal dynamics of crop growth and yield.