Peanut Irrigation Management Using EXNUT and MOISNUT Computer Programs1

Abstract Economic benefits from irrigating peanuts in the humid Southeast are often marginal or negative because proper consideration must be given to the complex relationships of plant, soil, pest and weather. Computer programs EXNUT and MOISNUT were developed to consider these complex relationships and to recommend timely irrigation of peanuts. A 3-yr study was conducted to evaluate the feasibility of using these computer programs for scheduling peanut irrigation on sandy and medium textured soils in Georgia. During 1994-1996, irrigation was applied two to nine times as recommended by these two computer programs. Net returns to irrigation were $490/ha higher for irrigated plots with these two programs than for nonirrigated plots. Serious compaction problems negated irrigation benefits in 1994 on the medium textured soil, and poor fertility and high disease pressure on the sandy soil negated irrigation benefits in 1995. Without these problems, the average benefit was $920/ha. During 1996, the irrigation ...