Effect of tree pruning on net assimilation rate (NAR) and crop growth rate (CGR) of dry season sorghum (Sorghum Bicolor (L.) Moench in the semi and zone of Nigeria

Abstract

The effect of balanites aegyptiaca, Prosopis juliflora and Acacia nilotica on Net Assimilation Rate (NAR) and Crop Growth Rate (CGR) of dry season sorghum, (Sorghum bicolor(L.) Moench) was investigated in October/November, 1995.  B. aegyptiaca were small and so were not pruned but P. juliflora and A. nilotica were pruned.  The result showed that the effect of tree species on sorghum varied with tree species such that B. aegyptiaca did not reduce Net Assimilation rate (NAR) and therefore Crop Growth Rate.  Pruning P. juliflora significantly (P<0.05) improved Net Assimilation rate and consequently Crop Growth Rate over the unpruned treatment.  However, A. niloticaI whether pruned or unpruned as well as unpruned P. juliflora inhibited Net Assimilation Rate and Crop growth in sorghum significantly (P<0.05) compared with the small canopy B. aegyptiaca and the non tree control.  Competition for limited moisture and light was responsible for decrease in assimilation per unit area of leaf resulting in low crop growth.  The result suggests that B. aegyptiaca or pruned P. juliflora can be planted with dry season sorghum.