Integrated Nutrient Management Improves Soil Biological Properties and Conserves Energy in Maize–Toria Cropping System

Continuous use of chemical fertilizers in the agricultural field leads to deterioration of the overall quality of the soil and increases environmental pollution. Understanding the impact of organic or inorganic nutrient management on soil biological properties and energy indices can be helpful in developing more sustainable fertilizer strategies. Hence, a field experiment was conducted at the Regional Research & Technology Transfer Station (OUAT), Semiliguda, Koraput, during kharif and rabi seasons of 2016-17 and 2017-18 to study the effect of integrated nutrient management (INM) on soil biological properties and energy indices of maize–toria cropping system. The experiment consists of twelve treatments and arranged in a completely randomized block design with three replications. The results of the study showed that all INM practices improved soil microbial populations and soil enzymes compared to soil test based fertilizer recommendation (STBFR) in maize–toria cropping system. However, highest population of bacteria (30.5 × 106 cfu g-1 soil), fungi (46.0 × 104 cfu g-1 soil), actinomycetes (24.3 × 105 cfu g-1 soil) and soil enzymes such as urease (185.4 µg NH4+-N2 g soil-1 h-1), acid phosphatase(393.0 µg PNP g soil-1 h-1)and dehydrogenase (274.2 μg TPF g⁻¹ soil 24 h⁻¹) were found with the application of STBFR + Green manure with cowpea + Farmyard manure (FYM) @ 5 t ha-1 + Biofertilizers (Azotobacter + Azospirillum + Phosphorus solubilizing bacteria (PSB) @ 4 kg ha-1 each). Increase in soil microbial population and enzymatic activity is an indicator of good soil conditions for crop growth, which was achieved through the integration of organic and inorganic fertilizers. The highest energy use efficiency (12.8), energy productivity (0.43 kg MJ-1) and net energy gain (250.9 MJ ha-1 x 103) were also recorded with same INM practice. Considering all biological properties and energy indices, the application of STBFR + Green manure with cowpea + FYM @ 5 t ha-1 + Biofertilizers (Azotobacter + Azospirillum + PSB @ 4 kg ha-1 each) was the most efficient integrated nutrient management option for maize-toria cropping system in the experimental region.