Changes in labile P status under different cropping systems in an arid environment

Field experiments were conducted to investigate the changes in labile P status due to crop rotation, residue incorporation, and tillage in the rhizosphere of desert forest trees and fruit plants. Labile P status, which decreases gradually with the soil depth, was 15% higher in untilled plots than tilled ones after 3 years of cropping. Legume crops in rotation with pearl millet increased the labile P status by 9-25%. Application of composted residue at 4 t ha(-1) increased the labile P status by 41%. The labile P status in the rhizosphere of desert forest trees and fruit plants was increased by 13-70% and 10-75%, respectively. No relationship was observed between the labile P status and dehydrogenase and alkaline phosphatase activity, but acid phosphatase activity in the rhizosphere may influence the labile P status (r = 0.551, n = 15, p < 0.05). Prosopis cineraria among desert forest trees, Emblica officinalis among fruit plants and clusterbean under crop rotation had the ability to maximize the labile P status in the soil under and environments. (c) 2004 Elsevier Ltd. All rights reserved.