Importance Of Rainfall Distribution
The average annual or seasonal rainfall at a place does not give sufficient information regarding its capacity to support crop production. Rainfall distribution pattern is the most important. This is illustrated by taking examples of Hyderabad and Solapur. These two locations are 500 km apart but have very similar amount of total rainfall (742 mm at Solapur, 764 mm at Hyderabad). At both the places, more than 75% of total rainfall is received September. However the distribution of rainfall at Solapur is highly erratic during Kharif. In comparison, Hyderabad has more dependable rainfall distribution pattern and thus more favorable for Kharif cropping than Solapur (Virmani et.al. 1982).
Field experiments at these two locations have shown that at Hyderabad, it is rossible to produce more that 500 kg grain ha-1 on deep Vertisols by adopting pigeon pea + maize intercropping C- maize – chickpea sequence cropping under good agronomic management. At Solapur Kharif cropping is undependable for a long duration crops but short duration crops of pearl millet sunflower or grain legume in Kharif followed by rabi Sorghum or gram is successful.