Long term effect of root management practices on rooting pattern in Dalbergia sissoo and grain yield of mustard under agrisilviculture system

Abstract

Root management is a potential tool for minimizing competition between tree and crops grown together in agroforestry systems. To investigate the long term effect of deep /shallow ploughing on root density of trees and their impact on crop yield, a field study was carried out at NRCAF Jhansi during 2003-04 to 2008-09 with root management practices i.e., deep ploughing and shallow ploughing. Mustard (Brassica Juncia L. Czernj. & Coss.) was taken as intercrop. Deep ploughing significantly had lower root length density (RLD) over shallow ploughing (0.165 cm root length cm-3 cm soil volume) at 0-15 cm soil depth but at 15-30 cm soil depth differences were not significant. Root length density was significantly higher at 0.5 m away from tree base as compared to 1.0, 2.0 and 3.0 m away from tree base but difference in RLD between 3.0 m and 4.0 m away from tree base was not significant. Root length density decreased with increasing distances from tree base under deep and shallow ploughing at 0-15 and 15-30 cm soil depth. Deep ploughing had significantly higher mustard yield (102.23 g m-2) than shallow ploughing (84.02 g m-2) and on per hectare basis, the deep ploughing gave 28% higher grain yield of mustard than shallow ploughing. The competition between tree and crop was higher at vicinity of tree and it decreased with increasing distances from tree base. Linear regression equations fitted between grain yield and distances from tree base indicated that average crop yield was 21.46 g m-2 at 0.5 m from tree base which would increase by 57.15 gm2 for each meter increase of distance from tree base up to 4 meters distance under deep ploughing. Similar pattern was also found in shallow ploughing but the yield was 16.0 g m-2 at 0.5 m from tree base and increment in yield with per unit distance was 50.40g m-2 up to 4 meter.