Response of groundnut (Arachis hypogaea) to irrigation in different water-table conditions

A field experiment was conducted with 'OG 85-1', a spanish bunch groundnut (Arachis hypogaea L.) during summer 1992 and 1993 on sloppy terraced field having clay loam texture where water-table fluctuated within 50 +/- 10, 90 +/- 10 and 110 +/- 10 cm below the surface. In each water-table condition, the crop was irrigated at 0.2, 0.4, 0.6, 0.8, 1.0 and 1.2 IW : CPE (IW = 60 mm). Pod yield increased significantly from 11.6 q/ha at stress (0.2 IW : CPE) to 22.5 q/ha at wettest regime of 1.2 IW : CPE and from 14.7 q/ha in 5 0 +/- 10 cm to 20.3 q/ha in 110 +/- 10 cm water-table condition. Response t o irrigation was quadratic under 50 +/- 10 and 90 +/- 10 cm water-table con ditions, with optimum irrigation and water requirement of 8, 10, 48.4 cm an d 66.8 cm respectively. In 110 +/- 10 cm water-table condition the response was linear. Optimum water-table depth was estimated to be 118.5 cm. Irriga tion (I) x water-table (W) effect was significant.