BLOCK-WISE PLANNING OF CROP AND WATER RESOURCES OF DURG DISTRICT
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Date
2012
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Indira Gandhi Krishi Vishwavidyalaya, Raipur
Abstract
The state of Chhattisgarh receives an average annual rainfall ranging from 1200 to 1600 mm which is considered to be quite enough amounts for successful crop production. Even with such ample availability of rainwater, the seasonal droughts especially during critical crop growth stages during September to October months are recurring phenomenon throughout the state under rainfed condition rice cultivation. The drought occurrence is not due to lack of rainfall but due to erratic distribution resulting in unstable crop yield. Due to this recurring drought feature and nonavailability of adequate rainfall at critical growth stages, the average rice yield is very low in the study area. Higher rice yield is possible under rainfed condition only if crop and rainwater management planning is made in accordance with rainfall behavior. Efficiently managing natural resources is a key factor for obtaining sustainable productivity in a watershed under rainfed farming. Therefore, a study entitled “Blockwise Planning of Crop and Water Resources of Durg District” was undertaken. In study, probabilistic estimates of rainfall were made at six levels of exceedence probability viz. 25, 40, 50, 60, 75, and 80 percent by fitting appropriate distribution. The normal distribution was found good fit for the periods of monsoon rainfall and stable rainfall months i.e. July and August. The expected monsoon rainfall at 75 and 80 percent probability exceedence were found to be 743.9 mm and 669.04 mm at Durg block,733 and 649.5 mm at Dhamdha block and 884.5 842 mm at Patan block respectively. Probability weekly rainfall was also worked out at all the three study block and it was found that in the weeks coinciding with nursery and reproductive stages of rice crop were well below the ET demand at these stages. Among the three blocks, Dhamdha block was found to experience more shortage of rainwater at critical growth stages in comparison to Durg and Patan blocks. In the study, the dry spell analysis was also carried out. It was found that 7 days dry spell occurs at Durg block whereas at Dhamdha and Patan blocks, the dry spells of only 5 and 4 days were found at 25% probability of exceedence of continuous dry days during the weeks. It was also found that the onset of effective monsoon occur between 16-18 June at the three study blocks whereas, the earlier probable date of withdrawal of effective monsoon was 9 days earlier at Dhamdha block as compared to other two blocks, indicating shorter monsoon was also made to determine dry and wet spells occurring at the study blocks. It was found that during 23-26 SMW (nursery period) and during 37-40 SMW (reproductive stage), the rainfall deficits were of higher magnitude indicating need for supplemental irrigation. Based on the above analysis of monsoon and rainfall characteristics a comprehensive crop-water management plan was suggested for the study area.