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

Krishna Prasad Bhattarai, Tej Narayan Mandal


Relationship between soil microbial biomass and fine 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 fine roots (0-30cm depth) was estimated in summer, 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 fine root biomass was significantly higher in HSF than TSF. Distinct seasonality was observed in soil microbial biomass and fine root in both forests. Soil microbial biomass is the main source of nutrients for the plant which showed opposite relationships with fine roots. Soil microbial biomass showed maximum value during summer season might be due to its accumulation when plant growth and nutrient demand are minimum. On the other hand, fine 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, fine root mortality transfer considerable amount of organic matter and nutrients in forest soils which may enhance the level of soil microbial biomass.


Fine Root Biomass; Relationship; Soil Microbial Biomass; Seasonality; Sal Forests.


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