Net Shoot Production and Biomass Transfer Rates in a Mature Grassland Ecosystem

Net shoot production in a mature Mixed Prairie community was estimated at 296 g/m[squared] by the harvest method. This estimate was obtained by adding the 126 g/m[squared] estimated as the loss that occurred from the green biomass during the growing season to community peak standing crop (170 g/m[squared]) that occurred in July. Productivity rates were 1.5 g/m[squared]/day to 2.7 g/m[squared] /day at peak standing crop. Biomass transfer rates were determined for three biomass categories: standing dead, fresh and humic mulch whose average standing crops were 198, 260, and 590 g/m. Transfer rates ranged from 0.11 to 1.8 g/m[squared]/day for standing dead to fresh mulch, 0.29 to 2.0 g/m[squared]/day for fresh mulch to humic mulch, and 0.71 to 2.1 g/m[squared]/day for losses from humic mulch. Respiration was estimated at 962 g/m[squared], equal to net shoot and root production . Net root production was estimated by multiplying the average root standing crop by a turnover rate coefficient. Gross production for the community was estimated at 1924 g/m[squared].