Soil microbial characteristics in sub-tropical agro-ecosystems of North Western Himalaya

Abstract

Eight predominant land use systems, viz. agriculture (T1), horticulture (T2), agrisilviculture (T3), silvopastoral (T4), agrihorticulture (T5), agrihortisilviculture (T6), forest (T7) and grassland (T8) of subtropical parts of Himachal Pradesh were selected along two altitudinal ranges A1 (365-635 m amsl) and A2 (636- 914 m amsl) to observe the variation in soil microbial activity and microbial characteristics. Agroforestry land uses and forest ecosystems displayed significantly higher microbial counts and microbial biomass carbon than agriculture and grasslands. The CO2 evolution (soil microbial activity) was found higher inagrisilviculture, agrihortisilviculture, forest and grassland use systems at both altitudinal ranges. Soil biological properties (microbial count, microbial biomass and microbial activity) were maximum in forest landuse system. Among the agroforestry land-use systems, agrisilviculture had significantly higher microbial counts. The maximum microbial count (164.50 × 105 cfu g-1 soil) was recorded in forest and remained statistically at par with agrisilviculture (162.34 × 105 cfu g-1 soil). Minimum microbial count (80.66 × 105 cfu g-1 soil) was observed in agriculture land use. At both the altitudinal ranges, the CO2 evolution was highest at 48 h time interval and decreased thereafter. The metabolic quotient (qCO2) indicated that C-use efficiency is higher in grassland use and agriculture land use systems than other studied systems.