Effect of Enriched Phosphocompost on Soil Biological Properties of Pearl Millet in Vertisols

Abstract

A field experiment was laid out with ten treatments replicated thrice in Randomized Block Design. Treatments comprised of  T1: control, T2: 100% RDF, T3: 100% RDF + 2.5 t bajra straw phosphocompost ha-1, T4: 100% RDF + 2.5 t cotton stalk phosphocompost ha-1, T5: 100% RDF + 2.5 t FYM ha-1, T6: 100% RDF + 5 t FYM ha-1, T7: 75% RDF + 2.5 t bajra straw phosphocompost ha-1, T8: 75% RDF + 2.5 t cotton stalk phosphocompost ha-1, T9: 75% RDF + 2.5 t FYM ha-1 and T10: 75% RDF + 2.5 t FYM ha-1. Soil biological properties were estimated at sowing, at flowering and harvesting of pearl millet. The experimental findings indicated that the soil microbial biomass were found to be increased at flowering than at sowing and further, gradually declined at harvest but higher than sowing stage. The significantly maximum soil microbial biomass C (212.42 µg C g-1 soil), N (70.72 µg N g-1 soil) and P (40.25 µg P g-1) soil contents were recorded with 100% RDF + 2.5 t cotton stalks phosphocompost ha-1 (T4) followed by 100% RDF + 2.5 t bajra straw phosphocompost ha-1 (T3) at flowering. Among the FYM treatments, the higher SMBC, N and P were noted with 100% RDF + 5 t FYM ha-1 over 100% RDF alone. Further, it was noticed that C and N mineralization rate were increased at flowering stage and then declined at harvest as compare to sowing stage. However, at harvest, the highest C (9.12 µg C g-1 soil d-1) and N (0.86 µg N g-1 soil d-1) mineralization were recorded with 100% RDF + 2.5 t cotton stalks phosphocompost ha-1 (T4) followed by 100% RDF + 2.5 t bajra straw phosphocompost ha-1 (T3). Significantly maximum dehydrogenase activity (61.17 µg TPF g-1 soil 24 hr-1), alkaline phosphatase activity (90.43µgP- Nitrophenol g-1 soil 24 hr-1), fungal (23 × 104cfu g-1 soil), bacterial (43 × 107cfu g-1 soil) and actinomycetes (41 × 106cfu g-1 soil) population were noted in the treatment receiving 100% RDF + 2.5 t cotton stalks phosphocompost ha-1 (T4).