Soil microbial population and yield of rainfed maize as affected by farmyard manure and biodigester liquid manure

A field experiment was conducted during Kharif (June-October) season 2010, under rainfed condition on red sandy loam soil to study the effect of farmyard manure (FYM) and biodigester liquid manure (BDLM) on soil microbial activity and yield of rainfed maize (Zea mays L.). A total of 13 treatments were laid out in a randomized complete block design with three replicates. The treatment combinations comprised of different levels of FYM (7.5, 10 and 12.5 t/ha) and BDLM-equivalent N (BDLME: 75, 100, 125 and 150 kg N/ha) compared with control [FYM 7.5 t ha^-1 + recommended dose of chemical fertilizer (RDF): 100:50:25 kg N:P:K/ha]. Application of FYM (12.5 t/ha) + BDLME (150 kg N/ha) recorded a significantly higher microbial population in soil after crop harvest total bacteria 50.5×10⁶ CFU/g, fungi 26.0×10⁴ CFU/g, and actinomycetes 23.8×10³ CFU/g), grain yield and straw yield compared to the rest of the treatments. Application of FYM (7.5 t/ha) + BDLME (75 kg N/ha) resulted in the lowest values for these parameters.