Impact of Organic and Inorganic Fertilizers on Microbial Populations at Various Altitudes of Nepal in Paddy Field Soil Systems

Soil microbes are important in processes such as soil aggregate formation, nitrogen cycling, compound breakdown, and other transformations. Understanding how microorganisms react to chemical and organic fertilizers is critical for long-term agricultural intensification. Soil samples were collected from three distinct ecological sites of Nepal including terai (Parwanipur), mid-hills (Pakhribas), and high hills (Jumla) during winter seasons for period of three years 2017, 2018, and 2019. Sandy loam soils of Agricultural Research Farm, NARC, were used to assess the effects of compost and inorganic fertilizers on microbial dynamics in the continuous rice wheat cropping system. The results showed that the farmyard manure-treated plot had the highest microbial population counts (fungal and bacterial) in all years, followed by the inorganically treated plot and the control at all locations. The Pakhribas location had the highest bacterial and fungal population across all treatments. A significant change in fungal population was observed between treatments and experimental sites. Across all treatments, the Jumla location had the lowest fungus population and Pakhribas had the highest