Title: Quantitative Biophysical and Yield Information for Precision Farming from Near-Real Time and Historical Landsat TM Images

The main goal of this study was to quantify within and between field variability in mapping agricultural crop types, their biophysical characteristics, and yield for precision farming applications using near-real-time and historical (archival) Landsat TM images. Data for 6 crops (wheat, barley, chickpea, lentil, vetch, and cumin) were gathered from a representative benchmark study area in the semi-arid environment of the World. Spectro-biophysical and yield relationships were established using a TM image of April 6, 1998 acquired to coincide with extensive ground truth data collection campaign for agricultural crops and other land uses. The relationships developed using this near-real-time acquisition was then used to quantify characteristics in the historical Landsat TM images of the same area for April 5, 1986 and May 4, 1988 which had limited ground truth data. Within and between field spatial variability in crop biomass, LAI, and yield were established and mapped for near-real-time and historical images with high degree of accuracy. For example, the LAI of 1998 was mapped at 81 percent overall accuracy (Khat = 76). For the 6 crops during 1998, within field variability (commission errors) were between 74 to 100 percent and between field variability (omission errors) was between 76 to 100 percent. Temporal variability in biomass and LAI were determined and mapped for researcher managed and farmer managed farms. Significant relationship existed between yields measured using sensors mounted on combine while harvesting and the estimated yields from Landsat TM derived indices.