Kravchenko, A.N., G.P. Robertson, K.D. Thelen, and R.R. Harwood.
Presented at the All Scientist Meeting (2004-10-08 )
The quantitative characterization of spatio-temporal variability in crop grain yields is an important component for successful precision agriculture applications. The objective of this study was to analyze and quantify effects of management practices and weather conditions on spatial variability patterns of crop yields based on the data collected at the Long Term Ecological Research site (Michigan). The treatments used in this study were two treatments with conventional chemical inputs (chisel plow and no-till) and two organic-based chisel plowed treatments with a winter leguminous cover crop (low chemical input and zero chemical input). The data consisted of corn-soybean-wheat yields collected via combine monitors from 1996 to 2001. The studied yield variability characteristics included coefficient of variation and sample variogram behavior near the origin. Stressful conditions, regardless of the stress origin, increased the overall yield variability (coefficient of variation) as well as the small scale yield variability (variogram nuggets and variogram slopes near the origin) making yields more sensitive to the small scale variations in growth conditions due to soil and micro-topographical differences. During the years with low precipitation both the coefficients of variation and the small scale variability were often significantly higher in the zero chemical input treatment than in the treatments that received fertilizer inputs.Back to meeting | Show |