Determination of rainfed crop growing period in Narmada Basin, India

Abstract

An attempt has been made to estimate the length of crop growing period with the help of soil moisture
conditions for rainfed crops in Narmada Basin, India. For the present study daily rainfall data of at least 35
years have been collected from Indian Meteorological Department (IMD, Pune for 47 rain-gauge stations within
the basin. The daily have been converted into weekly data. Probabilistic analysis of rainfall has been carried out
by using the technique of Incomplete Gamma Distribution. To estimate the beginning of growing period, weekly
data of precipitation and potential evapo-transpiration along with weekly dependable precipitation (20 mm)
have been considered. The end of growing period has been determined by using the data of AE/PE from the
WATBAL model. Available soil moisture condition is computed by using soil moisture adequacy index.
The study reveals that the average length of growing season for shallow black and skeletal soils varies
between 14 and 20 weeks whereas for medium and deep black soils it varies between 16 and 25 weeks and 17
and 28 weeks respectively. The probabilistic analysis of moisture availability indicates that the period of
excellent moisture adequacy differs according to rainfall amounts and depth of soils from place to place.