Soil changes following long-term cultivation of pulses

Studies were conducted on Entisols to understand the effects of continuous pulse cultivation on soil chemical, physical and biological properties by comparing with continuous non-pulse crops and uncultivated soils. Soils of a Typic Ustochrept, developed from the same parent material, from 16-year-old pulse cultivation fields, non-pulse crop fields and uncultivated fallow fields in a location with uniform topography were analysed using a polyphasic approach combining traditional soil physical and chemical analysis, culture-dependent and independent microbiological analysis and enzymatic analysis. Among the soil physical properties, only soil aggregate stability and soil compaction showed significant improvement in soils tinder pulses than non-pulse crops. Compared to uncultivated fallows, the soil pH after pulse cultivation was about 1 unit lower while non-pulse crop cultivation reduced it by 0.36. The chemical and biological variables that contribute most to the discrimination of the pulses effect and non-pulse crops effect on soil quality are organic carbon (C), microbial biomass C, nitrogen (N) and biomass ninhydrin-N, and secondary variables related to N cycle;nitrate (NO3-N), organic and total soluble N. The enzyme activities were significantly higher in soils after pulse cultivation than after non-pulse crops or uncultivated fallow. The soil quality of pulse cultivation fields seems to be markedly different to that of non-pulse crop fields and uncultivated fallows in terms of all the variables studied.