Spatial Stability of Production in Irrigated and Non-Irrigated Farmers' Fields

Due to their development and topographic heterogeneity, soils in farmers’ fields in Kentucky and beyond are typically variable. This variability reflects different growing conditions for field crops and results in crop yield variability despite uniform application of resources, such as seeds, fertilizers and pesticides. The result is spatial variability in water and nutrient use efficiency which raises concern because an important sustainability goal of maximum resource use efficiency is not reached. To develop decisions for better managing resources and soils, we need to understand the spatial variability pattern of crop yield. The objective of this study is to find answers to the following questions: a) Does the same field exhibit similar or different variability patterns over different years? b) What are the main triggers of spatial crop yield variability, weather, crop species, topography, or soil variability?