Rainfall probability analysis of the western Odisha plateau region for sisal (Agave sisalana Perrine ex Engelm.) based cropping system

Abstract

Daily rainfall and temperature data of recent past 10 years (2001-2010) recorded at the Meteorological Observatory of Sisal Research Station (23.05°N, 84.23°E, and 256.03 m above MSL), Bamra, Sambalpur,-Odisha were analysed to understand the variability and probability of rainfall for sisal based cropping-system in the tribal dominated western Odisha. The mean annual rainfall was 1230.6 mm from 59 rainy-days. The maximum contribution of rainfall was in the kharif season (90.4%). Among standard-meteorological weeks (SMW), 26-29 SMW received the highest rainfall (465.1 mm) which is 38% of-the total rainfall. In a single week the highest rainfall was in the 29th week (140.4 mm). It was computed-that 42.5% of the months were normal months and 32.5% of months faced water deficit situation. Only-four months in a year (June to September) had 100% probability of getting 100 mm rainfall. Expected-monthly rainfall of 250 mm is obtainable only in July and August. Therefore, sowing of rabi crops need-to be completed in early October to get the benefit of residual soil moisture from August rain as well as-to utilize the rain received in October. Mustard can be sown in October utilizing the available moisture; however, it needs assured irrigation during November-December when the probability of getting 50 mm-rainfall is very low (4-10%). In a year, there are two phases of deficit rainfall for sisal and sisal based-cropping system and they are January to May (Phase-I) and October to December (Phase-II). During-June to September, the rainfall is much excess to the ETc demand for sisal and therefore, care is to be-taken to remove the excess water from the sisal field having little natural slope for achieving better-growth and fibre yield.