Fine root biomass and soil properties in burnt and unburnt community grasslands of Cachar district, Assam, Northeast India

Community grasslands, inhabited by Imperata cylindrica, in northeast India contribute culturally to the rural landscape in the region. A study carried out to examine the fine root biomass and soil properties of these grasslands. Using iron cores, dry matter of fine roots and some soil parameters were determined sequentially across different depths. The results revealed that fine root biomass dynamics followed unimodal growth curve with one peak during the study period. In burnt plot, fine root biomass varied from 95.8 - 199.8 gm/m2, 47.9 - 94.2 gm/m2 and 27.0 - 58.7 gm/m2 in 0-10 cm, 10-20 cm and 20-30 cm depths, respectively. The corresponding values for unburnt plot were 99.9 - 206.7, 51.6 - 94.63 and 27.0 - 58.9 gm/m2. Fine roots were concentrated in the surface soil layer and decreased down the soil profile. In terms of the temporal variations, the maximum accumulation of dry matter was reported during the winter months. High content of soil organic carbon (%) and nitrogen (%) were recorded in the topsoil in contrast to the subsoil over two plots. The data indicated that the soil organic carbon and fine root biomass were significantly correlated at p < 0.001. The carbon stocks of topsoil were recorded as 10.79 and 9.52 t C/ha for burnt and unburnt plots, respectively.