Skip to main content
ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Publications at this Location » Publication #96362


item Camp Jr, Carl
item Sadler, Edward

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: The site-specific application of irrigation water and fertilizer should offer opportunities to conserve water, to reduce drought or flooding stress, and to reduce loss of fertilizer or pesticides from the field. To accomplish site-specific irrigation and fertilization, two center pivot irrigation systems were modified to permit a range of water and chemical application rates to areas about the size of a 2-car garage. For these areas, a computer with specialized software and a database of cultural information selects one of eight water application depths. These machines are one part of a three-part management system that also includes agronomic information(crop yield response) and a management strategy (e.g. maximum profit or minimum environmental damage). Now that these site-specific irrigation machines have been developed, they can be used in research to determine the agronomic and management information needed for commercial application of this technology.

Technical Abstract: Traditionally, site-specific farming suggests the management of fertilizers and pesticides for optimum crop yield on spatially-variable soils. In the southeastern Coastal Plain, research suggests that spatial yield variability may be caused primarily by water relations. Together, these requirements cause difficulties in managing water and chemical applications swith conventional center pivot irrigation systems. Site-specific center pivot irrigation systems were developed to independently apply variable rates of water, nutrients, and pesticides to 100-m**2 areas. Two commercial center pivot systems were modified by adding manifolds and nozzles in 13 segments along the truss to provide eight application depths within each segment. Also, a programmable, computer-controlled management system was added to provide the appropriate application rate for each area and to collect and store data. Control is based on stored GIS data but current conditions can be updated via dynamic measurements. Infrared thermometers mounted on each pivot provide soil surface and crop canopy temperatures, which can be used for crop and soil maps or real-time feedback for system management.