Effect of soil type and nitrogen levels on the productivity and crop water balance in rainfed diploid cotton (6ossypillm arboreurn)

Abstract

An experiment was conducted during 2000-2002 to study the effect of soil types and N levels on rainfed 'AKH 4' cotton (Gossypium arborezm~a)n d analyze the yield variations using soil dynamics, crop water balance and Nyield relationships. The soils were shallow Inceptisols underlain with weathered basalt (S,) and deep Vertisols (S,) and N levels were: No 0, N, 40, N, 80 and N, 120 kg Niha. Cotton on shallow soil gave 61% more yield, 49.7% more dry matter and absorbed 45.7 % more N than in deep soil. Soil x N interaction was significant and in 2000-01 the yield and boll number increased significantly up to 80 kg Niha on shallow but only up to 40 kg Niha on deep soil. The N yield applied relationship was quadratic during both years in deep soil and linear in shallow soil during 2000-01. Crop water balance model using daily rainfall could explain yield variations due to terminal deficit water stress but could not account for the intermediate excess water stress which adversely affects the yield of G. arboreum particularly on deep soils.