Soil quality parameters vis-a-vis growth and yield attributes of sugarcane as influenced by integration of microbial consortium with NPK fertilizers

Intensive agriculture involving high crop intensity, unavailability of organics, and higher use of straight fertilizers causes imbalanced use and deficiencies of several other macro and micronutrients. Nutrients supply through the integration of microbial consortium containing Gluconacetobater diazotrophicus, Trichoderma harzianum, and Pseudomonas fluorescens can reduce the requirements on the one hand and can also increase the response of chemical fertilizers. Thus we had planned the present experiment with the objectives (i) to determine the effect of integrated application of microbial consortium (MC) and NPK fertilizer on soil quality parameters and crop growth and yield attributes and (ii) to assess the effect of integration on agronomic efficiency of N, P and K and find out the possibilities for reduction in applied doses of NPK, if any. Five treatments viz., T(1); N(0)P(0)K(0); T(2): N(75)P(13)K(25); T(3): N(150)P(26)K(50); T(4): N(75)P(13)K(25) + microbial consortium and T(5): N(150)P(26)K(50) + microbial consortium containing new strains of Trichoderma harzianum, Gluconcetobacter diazotrophicus, and Pseudomonas fluorescens (CFU 10(9–10) per ml liquid culture) were evaluated under four replications in a randomized block design (RBD). Experimental results indicated that integrating microbial consortium and NPK fertilizers' application proved effective in improving soil organic carbon, soil microbial population, microbial biomass carbon, microbial biomass nitrogen, and soil respiration. Integrated use of microbial consortium with NPK also improved the cation exchange capacity of soil and roots. However, the growth and yield attributes, nutrients uptake, sugarcane, and sugar yields also revealed a positive effect of microbial consortium's integrated application with NPK. The integration of MC and NPK also improved the agronomic efficiency of applied nutrients (NPK). Reduction of 50% NPK with these microbial consortia (Trichoderma harzianum, Gluconcetobacter diazotrophicus, and Pseudomonas fluorescens) was found better than the application of full NPK through chemical fertilizers. Thus application of N(150)P(26)K(50) with microbial consortium can sustain soil fertility besides improving sugarcane and sugar yields in subtropical Indian conditions.