Appraisal of long-term rainfall trends and rainfall erosivity in diverse agroclimatic zones of Chhattisgarh state, India: Implication for soil and water conservation measures

Abstract This study delved into the trends of rainfall and rainfall erosivity (R-factor) over a span of 120 years (1901–2020) using monthly precipitation data from 16 stations in Chhattisgarh state, India. Various statistical methods including homogeneity tests, non-parametric trend tests, and Sen's slope estimator were employed to discern the trends and slope values. The results, at a 5% significance level, underscored a significant increasing trend in rainfall for the Bastar plateau, while the Chhattisgarh plains, Northern hills, and Chhattisgarh state exhibited a declining trend in annual rainfall. However, no specific trend was observed in pre- and post-monsoon seasons. During the winter season, the Bastar plateau, Northern hills, and Chhattisgarh state experienced declining rainfall, whereas the Chhattisgarh plains showed no discernible trend. Notably, the Northern hills exhibited the highest mean annual R-factor (12519.4 MJ mm ha-1 h-1 year-1), followed by the Chhattisgarh plains (11587.7 MJ mm ha-1 h-1 year-1) and the Bastar plateau (9633.5 MJ mm ha-1 h-1 year-1). On the broader scale, the annual R-factor trend for Chhattisgarh state indicated a decline, estimated at a rate of 0.74 MJ mm ha-1 h-1 year-1. This decline was attributed to a reduction in overall rainfall, although it's important to note that this decrease in R-factor doesn't necessarily signify a decline in soil erosion or soil health deterioration. To adapt to the varying rainfall patterns, it's imperative to implement region-specific measures that can effectively address both increasing and decreasing trends in rainfall. This targeted approach is crucial for sustainable management of soil erosion and preservation of soil health in the study area.