Analysis of rainfall and crop cultivation practices in MRBC AREA, Gujarat

The vulnerability of natural systems to rapid changes in climate pattern is regarded as one of most challenging issues in recent years. This paper analyzes the annual rainfall pattern in the Mahi Right Bank Canal (MRBC) irrigation command area located in central Gujarat and evaluates its effects on cropping pattern, crop plantation schedules observed by the farmers in the command area under the study. The annual rainfall trend for Borsad meteorological station between 1876–2008 (133 years) shows a decreasing trend. The one day rainfall data for the years 1962–2008 are analyzed to identify the maximum one day rainfall and the day of occurrence. Statistical analysis is carried out to obtain the mean and standard deviation of number of rainy days for different ranges of one day rainfall. Trends are obtained for number of rainy days for one day rainfall in different ranges for the years 1962–2008. Results reveal that there have been six occasions in the last four years (2005–08) when one day rainfall has exceeded 120 mm. The major crops in the study area are paddy and tobacco. Results show that the average maximum one day rainfall is 121.5 mm and is occurring on 218^th Julian day. This being a transplantation period for tobacco, it is not the favorable condition for the crop. It is thus advisable for the farmers to delay tobacco plantation as heavy rainfall results in flooding of agricultural fields and causes damage to transplanted tobacco crop which are normally 4 to 6 cm in size. The cropping pattern in MRBC command area as per project plans and that actually developed is different, probably due to above mentioned reason. The MRBC engineers and project administrators are also required to plan the canal operation schedules as per new cropping pattern.