Validation of EXNUT for Scheduling Peanut Irrigation in North Carolina1

Abstract

During crop years 1989-1992 EXNUT concepts and a version of EXNUT modified for North Carolina conditions were evaluated. This version was revised and evaluated on 20-25 peanut fields during crop years 1993, 1994, 1995, 1996, and 1997 when average yields of 4360, 4890, 4640, 4530, and 4770 kg/ha, respectively, were obtained. These yields averaged 880 kg/ha higher than average yields produced on these irrigated fields prior to 1993 and 1660 kg/ha higher than the average county yields during 1993-1997. The farmers and county agents reported that irrigation scheduled by EXNUT provided an estimated 500 kg/ha increase in yields. Costs of running EXNUT were estimated at $5.14/ha. Using these estimates, net returns from using EXNUT instead of normal irrigation scheduling by the farmer was $272.76/ha. Average compliance of farmers with EXNUT water scheduling recommendations was 85 and 75% for wet years (1994 and 1996) and dry years (1993, 1995, and 1997), respectively. On the average, a 71% or higher compliance with EXNUT recommendations on fields with sandy- and medium-type soils resulted in yields greater than 4480 kg/ha, making irrigation of peanuts feasible in these fields at a world market price as low as $350 per metric ton. Every percentage point increase in compliance with EXNUT recommendations on these fields resulted in an increase in yield of 50 and 110 kg/ha during wet and dry years, respectively. Yields from fields with heavy type soils averaged only 3850 kg/ha because of excessive disease and harvest losses. On the average, peanuts can be produced on this heavy-type soil at world market prices of $410/metric ton if compliance with EXNUT recommendations is at least 80%. This 9-yr study is an example of how expert systems can be transferred through cooperation of researchers, extension specialists, and users.

Nitrate leaching, water-use efficiency and yield of corn with different irrigation and nitrogen management systems in coastal plains, USA

“…The first irrigation treatment was based on the Irrigator Pro for Corn expert system (IP) that was developed by the USDA-ARS-National Peanut Research Laboratory, Dawson, GA. This expert system has been tested extensively in uniformly irrigated fields [8][9][10][11]. In this research, Irrigator Pro for corn was implemented using spatial management zones corresponding to variable soil types.…”

Evaluating a nonionic surfactant as a tool to improve water availability in irrigated cotton

“…Irrigation after all treatments was scheduled by Irrigator Pro for Cotton version 2Ð0 in 2006 and version 2Ð0.2 in 2007. Irrigator Pro is a decision-based software program for managing irrigation scheduling and was developed and released by the USDA-ARS-NPRL in collaboration with the University of Georgia (Davidson, et al, 1998). The model is designed to avoid crop stress while triggering irrigation at the most efficient…”

Comparison of Irrigation Systems and Fungicide Programs in Virginia Market-type Peanut

“…A series of 10 rain gauges were spaced equally through the radius of sprinkler nozzle on either side of OSI pipe. Frequency and amount of irrigation was based on recommendations from the Irrigator Pro model for peanut (5). Overhead sprinkle irrigation was supplied as sequential applications of 18 mm to satisfy irrigation requirements.…”

“…Rainfall during this period was 504 mm (2003) and 510 mm (2004) ( Table 2). Water was applied each day with SDI from Monday through Friday at a rate of approximately 5 mm/day as needed to satisfy recommendations from Irrigator Pro (5). Irrigation was reinitiated 4 days after rainfall in excess of 18 mm and was continued when rainfall events were less than 18 mm.…”