Assessment of biological indicators of soil quality to enhance productivity of pulse crops

Abstract

An assessment of biological indicators of soil quality was conducted in three blocks of pulse growing zones of Virudhunagar district viz., Sattur, Aruppukottai and Tiruchuli which were classified into three categories viz., low yielding (less than 400 kg ha-1), medium (400 to 700 kg ha-1) and high yielding (more than 700 kg ha-1) zones. The biological indicators viz., soil organic carbon content, microbial respiration rate and dehydrogenase enzyme activity of soil were assessed for each zone. The low organic carbon content (1.74 g kg-1) in the low yielding zone reflected in the low mean soil respiration rate of 2.34 mg CO2 kg-1d-1. In the high yielding zones, the respiration rate ranged from 2.45 to 7.45 mg CO2 kg-1d-1 with a mean value of 4.48 mg CO2 kg-1d-1. About 70 percent soil samples from high yielding zone recorded high soil respiration rate. The average values of dehydrogenase enzyme activity was higher in 82% of high quality soils where the farmers have practised proper nutrient management practices indicating that regular application of enriched FYM, Azospirillum and pulse wonder along with TNAU recommended dosage of fertilizers enhanced the yield and productivity of pulses.