Seasonal changes in biomass, net primary productivity and turnover of dry matter of para grass (Brachiaria mutica) under a mixed tree stand and in an adjacent open stand in northern India are presented. Both stands attained peak values of live shoot biomass in September with a higher 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 belowground 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 aboveground and belowground net primary productions in both stands were obtained during the rainy season. The total net primary production for para grass was about 15% higher under mixed tree stand than in the open. The turnover rates of total plant biomass were greatest in the rainy season and the least during the summer season. The system transfer functions showed that the production of para grass on both stands was aboveground-oriented, accounting for 85–87% of annual total net primary production.