Date of this Version
Increased interest in site-specific management of irrigated corn in Nebraska has identified the need for a decision-making framework for zone delineation. Zones based on static soil and landscape properties provide a valuable foundation for variable rate management strategies. The purpose of this project was to identify the optimal soil and landscape attributes for generating management zones (MZ) of relative productivity potential. Three producer-managed cornfields across Nebraska with varying soil types, topographic characteristics, and climate regimes were identified as research sites during the 2010 growing season. Nine soil and landscape attributes were identified as potential properties for estimation of productivity potential. The attributes were broken into three groups; soil properties, spectral wavebands, and landscape attributes. Correlations between independent attributes and grain yields were used for determining the optimal soil and landscape attributes for MZ delineation. Optimum attributes were imported into Management Zone Analyst software package (MZA) for zone delineation. Correlations at each research site determined different combinations of soil and landscape attributes as the most appropriate for delineation of MZs. The attributes used in this project were assumed to be static properties. Those properties are only part of determining productivity; in-season influences also affect productivity. Evaluation of using a single MZ delineation opertation for multiple fields proved to be unproductive. MZs in different fields that are determined to have equivalent soil and landscape properties in MZA do not represent equivalent productivity potential. Although sampling density of soil and landscape attributes will determine spatial resolution of management zones, the smaller the spatial resolution the greater the precision and accuracy of the management zones as it relates to production potential. Small-scale variability will potentially be overlooked when spatial resolution of management zones is increased. Results from this project provide farmers a foundation for sit-specific management of irrigated corn in Nebraska. Adaptability of in-season management is critical to account for climatic irregularity during the growing season.
Adviser: Richard B. Ferguson