Markov Chain Approach – Dry and Wet Spell Rainfall Probabilities in Planning Rainfed Rice Based Production System

For successful agricultural management and planning of soil water conservation measures, information about occurrence of dry and wet periods along with onset and withdrawal of rainy season is important. In this study Markov Chain model was employed to find the initial and conditional probability of occurrence of dry and wet weeks, onset and withdrawal of rainy season and weekly analysis of rainfall for Varanasi region. The average annual rainfall of Varanasi was found to be 1012.8 mm and coefficient of variation (CV) of 19.1%. The data on onset and withdrawal of monsoon indicated that rainy season starts effectively from 26^th standard meteorological week (SMW) (25 June-01 July) and remain active up to 42^nd SMW (15–21 Oct). During rainy season, the probability of occurrence of wet week is more than 50% except during 40^th to 42^nd SMW. Based on rainfall pattern and its distribution, different crop management strategies as well as remedies are suggested for optimal use of rainfall received during the monsoon season and maximize the crop production.