Biomass, composition and temporal dynamics of soil organisms of a silt loam soil under conventional and integrated management.

Abstract

Field plots (Netherlands) under conventional (CF) or integrated (IF) farming and cropped to winter wheat were sampled in 1986 for various soil organisms. Organisms were assembled in functional groups, based on their main food source and life-history characteristics. Total biomass of soil organisms was, on average, 690 kg C/ha under CF and 907 kg C/ha under IF during the growing season. Bacteria constituted > 90%, fungi ~ 5%, and protozoa < 2% of the total biomass. Nematodes and microarthropods were less important in terms of biomass C. Carbon flow through the protozoa annually was estimated to be 158 and 195 kg C/ha in CF and IF, resp., corresponding to 20% of the estimated bacterial production in both CF and IF. Nitrogen mineralization by the protozoa annually was estimated to be 30.5 and 37.6 kg N/ha in CF and IF, resp. Nematodes were less important than protozoa in terms of direct C and N transfer. The direct contribution from microarthropods was insignificant. Results are discussed in terms of effects of the soil biota, in particular the soil fauna, on C and N transfer in arable soil. (Abstract retrieved from CAB Abstracts by CABI’s permission)