Soil biological pools in traditional long-term rainfed rice ecosystems in hill agriculture

Abstract

The soils of stable hill rice ecosystems viz. mono-cropped lowland and upland terraces in the present study were characterized in terms of biological pools of carbon (C), nitrogen (N) and phosphorus (P) and compared (P0.01, paired t-test) and studied the pairwise correlation for kharif and rabi season. Seasonal fluctuation in soil pH and different fractions of C, N and P viz. soil organic C (SOC), microbial biomass C, N, P (MB -C, -N, -P), dissolved organic C (DOC), basal respiration (BAS), substrate induced respiration (SIR), extractable organic N (EON), potentially mineralizable N (pMN), dehydrogenase (DHA) and phosphatase activity (PHA) were observed for different rice ecosystems. C and N components in soils of stable lowland and upland terrace rice ecosystems seem to be self-sustained, but the major limiting factor was availability of P. Moisture content were observed to be a critical variable that control the size and dynamics of biological pools of C, N and P and the interrelationships among the parameters in different rice ecosystems.