Site specific crop management with a center pivot

Traditionally, site-specific farming suggests the management of fertilizers and pesticides but research in the southeastern Coastal Plain suggests that spatial yield variability may be caused primarily by water relations. Site-specific management of water and chemical applications is difficult with conventional center pivot irrigation systems. Site-specific irrigation systems were developed to independently apply variable rates of water, nutrients, and pesticides to 100-cm(2) areas. Two commercial center pivot systems were modified by adding manifolds and nozzles along the truss to provide eight application depths within each of 13 10-m segments. A programmable, computer-controlled management system uses stored GIS data to provide the appropriate application rate for each area but can also be updated via real-time soil and crop measurements.