Irrigation Method and Water Quality Effect on Peanut Yield and Grade

Peanut ( Arachis hypogaea L.), irrigated only recently in the coastal plain region of Virginia and North Carolina, is produced in an area where sodic deep water sources are more readily available than high quality shallow water sources. The objective of this work was to determine the effect of irrigation water quality and irrigation method on the yield and grade of peanut. Virginia‐type peanuts (cv. VA 81B) were grown on a Kenansville loamy sand (loamy, siliceous, thermic Arenic Hapludult) in Suffolk, VA from 1984 to 1987. Peanuts were irrigated with either overhead sprinklers or deep buried trickle lines using deep‐well (142 m) and shallow‐well (10 m) water. Trickle lines were buried 350 to 410 mm below each row. Deep‐well water had 220 mg Na L −1 , a pH of 8.5, and a sodium adsorption ratio (SAR) of 103. Shallow‐well water had 4.8 mg Na L −1 , a pH of 4.8, and an SAR of 3.1. Shallow‐well, trickle‐irrigated peanuts yielded 5003 kg ha −1 or 14% higher than the nonirrigated treatment. Deep‐well, sprinkler‐irrigated peanuts averaged 4374 kg ha −1 for 4 yr, which was 21 kg ha −1 lower than the nonirrigated treatment. The price of deep‐well, sprinkler‐irrigated peanuts was also lower than all other treatments due to lower percentages of extra‐large kernels, total sound mature kernels, and fancy pods. Deep‐well water applied below 300 mm through trickle irrigation produced peanuts of comparable quality and quantity as the shallow‐well, trickle, or sprinkler‐irrigation treatments. Irrigation of peanuts was beneficial in this humid region. There was no difference in peanut yield or grade when sprinkler or trickle irrigation was used with good quality irrigation water, but trickle irrigation required only 44% as much water. With a sodic water source, trickle irrigation was superior to sprinkler application.