Soil Microbial Biomass Carbon and Nitrogen in Himalayan Rangeland of Eastern Nepal: A Comparison between Grazed and Non-grazed Rangelands

Abstract

Soil microbial biomass plays an important role in nutrient transformation in terrestrial ecosystems. Microbial biomass is also an early indicator of changes in total soil organic carbon. Thus, the main objective of this study was to identify and quantify the present status of soil microbial biomass carbon and nitrogen with various management practices in Himalayan rangeland. To meet the aforementioned objectives, a field study was conducted in Tinjure Milke Jaljale (TMJ) eastern Himalaya Nepal in 2011-2013. Soil samples were collected from the depths of 0-15 cm at three soil cores in each quadrat. Quadrat size was 30*30 cm and core size was 4 cm in diameter and 15 cm deep. Composite soil sample was made while mixing all the samples of a quadrat. Five quadrats were taken from each subplot. Soil core was separated into three sections viz. 0-5, 5-10 and 10-15 cm profiles with 5 cm length of each slice. Soil sample analysis was carried out by the process of chloroform fumigation method. The Result showed that soil microbial biomass C ranged from 219.84 to 987.5 mg/kg. The soil microbial biomass C was increasing with decrease of grazing intensity of the rangeland and differences were significant. Similarly, the soil microbial biomass N with value of 207.72 mg/kg was significantly higher in occasional grazing plot than two other treatments. Both soil microbial biomass C and N values were in decreasing trend with increase of soil depth of the rangeland.