Rainfall Trend Analysis and Contingent Crop Planning for Temporally Non-Submerged Wetlands in North Bihar (Zone I), India

Abstract

North Bihar, particularly Zone I, is highly susceptible to climatic extremes such as floods and dry spells, posing significant challenges to agricultural sustainability. This study analyzes 100 years of rainfall data (1923-2022) and develops season-specific contingent crop plans for temporally non-submerged wetlands. Using Weibull’s probability method and regression analysis, seasonal rainfall trends were quantified. In the pre-monsoon season, Sitamarhi, Madhubani, and West Champaran exhibited significant increasing trends of 1.12 mm/year, 0.98 mm/year, and 1.25 mm/year respectively (p < 0.05), while Araria and Supaul showed non-significant trends. Monsoonal rainfall was relatively stable, with minor variations: Supaul (+0.35 mm/year) and Araria (-0.42 mm/year), both statistically non-significant. In the post-monsoon period, significant declining trends were recorded in Madhubani (–0.86 mm/year), Sitamarhi (-0.73 mm/year), and West Champaran (-1.05 mm/year), indicating reduced late-season water availability. These district-specific rainfall patterns guided the development of adaptive crop strategies, such as short-duration and climate-resilient varieties, enhanced water-use efficiency, and cropping calendars synchronized with actual monsoon onset. The study underscores the necessity of rainfall-based planning to boost farm productivity and resilience in climate-vulnerable North Bihar.