SEASONAL-VARIATION IN BIOMASS AND PRIMARY PRODUCTIVITY OF PARA GRASS (BRACHIARIA-MUTICA) UNDER A MIXED TREE STAND AND IN AN ADJACENT OPEN AREA IN NORTHERN INDIA

Seasonal changes in biomass, net primary productivity and turnover of dry matter of pam grass (Brachiaria mutica) under a mixed tree stand a nd in an adjacent open stand in northern India are presented. Both sta nds attained peak values of live shoot biomass in September with a hig her value under mixed tree stand (665 g m(-2)) than in the open stand (522 g m(-2)). The net aboveground production was 590 and 527 g m(-2) yr(-1) under mixed tree stand and in the open, respectively. The below ground net primary production was also greater under mixed tree stand (100 g m(-2) yr(-1)) than in the open (76 g m(-2) yr(-1)). Maximum abo veground and belowground net primary productions in both stands were o btained during the rainy season. The total net primary production for para grass was about 15% higher under mixed tree stand than in the ope n. The turnover rates of total plant biomass were greatest in the rain y season and the least during the summer season. The system transfer f unctions showed that the production of para grass on both stands was a boveground-oriented, accounting for 85-87% of annual total net primary production.