Relationship Between Soil Microbial Biomass and Fine Roots in Tarai and Hill Sal (Shorea robusta Gaertn.) Forests ofEastern Nepal

摘要

Relationship between soil microbial biomass and ?ne roots were studied in Tarai Sal forest (TSF) and Hill Sal forest (HSF) of eastern Nepal. Physico- chemical properties of soil were determined in upper (0-15cm) and lower (15-30cm) depth in the both forests. Soil microbial biomass (0-15cm depth) and ?ne roots (O-30cm depth) was estimated in Sl1l11I1‘lCI', rainy and winter seasons in both forests. Soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP) were higher in HSF than TSF whereas the values decreased depth wise in both the forests. Microbial biomass carbon (MB-C), nitrogen (MB-N) and phosphorus (MB-P) were higher by 66%, 31% and 9% respectively in HSF than TSF. Annual mean ?ne root biomass was signi?cantly higher in HSF than TSF. Distinct seasonality was observed in soil microbial biomass and ?ne root in both forests. Soil microbial biomass is the main source of nutrients for the plant which showed opposite relationships with ?ne roots. Soil microbial biomass showed maximiun value during summer season might be due to its accumulation when plant growth and nutrient demand are minimum. On the other hand, ?ne root showed maximum value during rainy season because of fast turnover of micro-organisms and optimum utilization of nutrients by the plants when growth and development remains at the peak. In conclusion, ?ne root mortality transfer considerable amount of organic matter and nutrients in forest soils which may enhance the level of soil microbial biomass.