干旱区生态环境知识资源中心

Tree-crop interface studies were conducted at National Research Centre for Agroforestry, Jhansi in an 8-year-old neem (Azadirachta indica A. Juss) plantation to evaluate growth performance and productivity of neem and understorey crop black gram (Phaseolus mungo). Photo synthetically active radiation (PAR) was highly correlated with vegetative growth and yield attributes of the crop. PAR decreased with increase in the age of the trees and reduction was 58%, 61% and 84% in 1997, 1998 and 1999 respectively as compared to 100% in the open. The reduction in grain yield was 60%, 71% and 80% in 1997, 1998 and 1999, respectively under the tree canopy which indicated that tree canopy management of neem was required to enhance PAR and crop yield. Although crop yield under the tree canopy decreased but the increased wood volume and fruit yield of neem trees gave higher economic returns than reduced yield of understorey crop. Neem trees attained mean current annual increment (CAI) of 65.04 cm for tree height, 2.07 cm for CD, 1.77 cm for DBH and 44.99 cm for crown diameter during March 1998 to March 2000. The mean annual litter fall by neem trees was 6059 kg ha(-1) at the density of 400 trees ha(-1) with potential return of 98, 2.25, 32 and 131 kg ha(-1) of available nitrogen, phosphorous, potassium and calcium.