Study of Rainfall Distribution Pattern and Its Variability in Bidar Region, Karnataka, India

Abstract

A case study has been done to study the rainfall distribution pattern and its variability for the selection of crops and cropping pattern of Bidar region, Karnataka with a predominant pigeon pea and sugarcane cropping systems. The study revealed that the overall mean annual rainfall of Aurad was 846 mm, which was distributed as 673.7 mm, 101.6 mm, 60.2 mm and 10.7 mm in monsoon, post monsoon, summer and winter respectively. The average annual rainfall of Bhalki was 874.7 mm with average rainy days of 51 days. The mean annual rainfall of Humnabad is 797 mm with 27 per cent variability spread over 50 mean rainy days. The analysis of rainfall data indicate that the average annual rainfall for the Basavakalyan was 759 mm spread over with a mean rainy days of 49.9 days. The mean annual rainfall for Bidar is 937.3 mm with coefficient of variation of 22.2 per cent indicated that the annual rainfall was more or less stable over the years. Within the rainy season, August was the highest rainfall contributing month (21.3 per cent) followed by July (19.9 per cent). Rainfall during monsoon season and its variability govern the cropping system of Bidar. There is an ample scope for rain water harvesting from July to September which can be utilized as crop saving irrigation as well as per sowing irrigation for succeeding rabi crops which are generally sown on residual soil moisture.