An experimental sprinklerhead may enable tomorrow's growers to direct precise amounts of water and fertilizer to every part of their field.

Known as a variable-flow sprinklerhead, the device would accommodate natural variations in soil type, slope or fertility throughout a field. For example, the sprinklerhead could apply smaller amounts of water and fertilizer to sandy areas prone to deep seepage than to clay soils.

Precise applications of water or fertilizer will reduce the chance that excess water will leach into underground water supplies, carrying farm chemicals with it, according to agricultural engineer Dennis C. Kincaid of USDA's Agricultural Research Service in Kimberly, Idaho. Kincaid and colleagues from the University of Idaho and Precision Irrigation Systems, Inc., Soda Springs, Idaho, are seeking a patent for their invention.

When the sprinklerhead is perfected, a needle or pin within the new nozzle would move smoothly in and out, reducing flow by up to 35 percent of the nozzle's full capacity. An electrical power source or another component, called a hydraulic actuator, would control the needle. Either power source can be activated by computer.

An article in the December issue of the agency's Agricultural Research magazine gives details. The article also is on the World Wide Web at:

http://www.ars.usda.gov/is/AR/archive/dec97/head1297.htm

Scientific contact: Dennis C. Kincaid, ARS Northwest Irrigation and Soils Research Laboratory, Kimberly, Idaho, phone (208) 423-6503, fax (208) 423-6555, Kincaid@kimberly.ars.pn.usbr.gov