Cultivation-dependent modulation of general and beneficial microbiota in summer and rainy season groundnut cultivation under different farming systems

This research investigated the influence of diverse farming practices on populations of general and beneficial soil micro-organisms in summer and rainy season groundnut cultivation. Over 4 years (2019–2022), four distinct farming practices; natural farming, organic farming, recommended package of practice, and conventional farming practice were assessed. The study revealed a significant impact of the application of organic inputs on microbial populations, with increased abundance of the general microbial populations (bacteria, fungi, and actinomycetes) from 2019 to 2022. The natural farming treatment demonstrated the highest microbial counts, reaching peak levels at the flowering stage in 2022 (186 × 105 cfu g−1 soil for bacteria, 49 × 104 cfu g−1 soil for fungi, and 38 × 103 cfu g−1 soil for actinomycetes) in the summer groundnut crop. The organic farming treatment also recorded a high abundance of the general microbial populations, with statistically similar numbers to that in natural farming. Beneficial microbial populations, including phosphate solubilising bacteria, Pseudomonas, Trichoderma, and Rhizobium, exhibited similar patterns, with natural and organic farming treatments consistently recording the highest counts across the 4 years. Conversely, the conventional farming practices resulted in lower numbers for beneficial microorganisms. Soil enzymatic activity, assessed through dehydrogenase, phosphatase, and urease assays, showed variations over time. Natural and organic farming displayed the highest enzymatic activity, indicating improved soil health. These findings underscored the positive impact of natural and organic farming practices on microbial populations and enzymatic activity, contributing to enhanced soil health and sustainable agriculture, in summer and rainy season groundnut cultivation.