Scope and method of study. The variability in wheat yields over time and space is substantial. Satellite imagery provides an opportunity to study the spatial and temporal yield variability on the farmers' fields at low cost. Multi-year satellite images for three selected fields are obtained to study temporal and spatial variability, using the NDVI index. Farmers provided detailed information on inputs and analysis of 0.1544-acre pixels reveals substantial temporal and spatial variability. Budgeting is used to compare site-specific and uniform applications of nitrogen.; Finds and conclusions. Fields with highly variable yields resulting from soil variations and manageable inputs will gain the most from this technology. Such soils can perhaps be more efficiently managed through spatially variable technologies. An approach that would benefit some producers is to identify patterns of yield consistency and inconsistency in different parts of each field. Costs of site-specific management can be reduced if those distinctly behaving parts of the field are relatively large in size. Smaller and numerous micro-units may make precision farming economically infeasible, especially in case of a crop like wheat. There are some important issues that need to be addressed to make the satellite-generated information more beneficial for wheat producers. The time that the satellite images are taken is very important. Farmers tend to tailor their farm management practices based on the information that becomes available during the course of crop production. The study of satellite images for a given field for a number of years can make the farmer more aware of problem areas within their fields. Farmers could decide to change tillage or other input practices to increase yields in certain areas. Availability of climatic information, like rainfall, for different micro-units could be important in analyzing spatial and temporal variability. However, obtaining that information could be costly, and while it might help explain yield variability, producers would likely still find it difficult to manage weather-related variability.
展开▼
