WATER HARVESTING BASED INTEGRATED FARMING SYSTEM FOR KVK FARM, ANJORA, DURG
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Date
2011
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Indira Gandhi Krishi Vishwavidyalaya, Raipur
Abstract
Adequate rainfall, river flows and fertile soils in Chhattisgarh Plains facilitate successful rainfed agriculture ,sometimes under the threat of in-season droughts resulting in instability in rice production. The study area of KVK Farm (20 ha) comes under Chhattisgarh plains with average rainfall of 1422 mm. The irrigation potential in the district is proportionately higher (39.2 % GSA) against the state figure (27.1 % GSA). The district has 1.1 % of irrigated area under tank irrigation which is lower than the corresponding state figure (3.5%). Therefore, there is ample scope of water harvesting based small tank irrigation. The optimal land and water use plan based on land use capability classification was framed out, adopting water harvesting and recycling, to increase the production and productivity of crops following the guidelines of Dy. Director General (Agricultural Extension), ICAR,. The main objective of the study was to work out the development plan, to design water harvesting and drainage system, to work out optimal crop plan and its economics for sustainable use and development of land and water resources. The KVK farm; was surveyed topographically, mapped land uses according to land use capability classification, estimated rainfall and runoff at 4 levels of probability of exceedance, designed drainage system and water harvesting system and formulated optimal crop plan for sustainable agricultural production. The prospective crops included in the optimal crop plan were selected by gathering field data in farmer’s field regarding crop productivity and its economics under both rainfed conditions as well as in irrigated condition. Daily rainfall data for past 21 years (1990-2010) were collected and analyzed statistically to determine the expected amount of rainfall at different probabilities of exceedance. In absence of any gauged data, daily runoff was estimated by USDA-SCS curve number method and its analysis was carried out to determine the expected amount of runoff at various probabilities of exceedance. Using this and other hydrological data, designs of existing and proposed water harvesting ponds and drainage system was attempted at 4 levels of probabilities of exceedance. The design of surface drainage was attempted for 5-yr, 24-hr rainfall, to mitigate water logging, considering 16 hours as the excess water removal time for vegetable, pulses, oilseeds etc., leading the runoff to water harvesting ponds that served as outlet. The stored water was recycled for irrigation to crops and also used for fish rearing. Optimization models for crop area and pond water allocation were formulated by LP model under rainfed and irrigated conditions. The overall economics of the crop production was worked out, considering the annual cost of water harvesting pond, rental value of land, interest on investment, annual maintenance cost etc. besides cost of production etc. The results of study indicated that rainfall (annual, monsoon, SMW: 26-39) as well as runoff (monsoon, SMW: 26-39) could be best fitted by normal distribution. The exponential distribution was found good fit for the periods of high variability of rainfall and runoff (SMW: 22-25, SMW: 40 – 43). The expected monsoon rainfall was worked out as 1112.2, 1023.4, 928.3 and 817.0 mm and the runoff amount was worked out as 521.1, 466.4, 407.7 and 337.4 mm at 50%, 60%, 70% and 80% probability respectively. The runoff constitutes 46.9%, 45.6%, 43.9% and 41.3% of rainfall at respective probabilities of exceedance. The optimal crop plan under rainfed condition at 50% probability resulted gross profit (Rs. 15.06 lakh), net profit (Rs. 4.9 lakh) with B/C ratio (1.48). Crops included were rice-2 ha, okra – 11ha during Kharif , and linseed- 12 ha, gram-1 ha in rabi season under rainfed condition. The optimal crop plan under irrigated condition for proposed pond at 50% probability of exceedance resulted highest gross profit (Rs.25.78 lakh) and net profit (15.30 lakh) with B/C ratio (2.5). Crop included were: rice-2 ha, tomato-10.0 ha, lentil 10.7 ha, linseed- 1.0 ha and linseed (rainfed) – 0.3 ha and fish rearing – 0.66 ha. Existing pond at 50% probability of exceedance resulted highest gross profit (Rs.20.2 lakh) and net profit (10.3 lakh) with B/C ratio (2.04). Crops included were: rice-2 ha, tomato-10.0 ha, lentil 1.04 ha, linseed- 1.0 ha and linseed (rainfed) – 9.96 ha and fish rearing – 0.71 ha under water harvesting based irrigated condition. The existing pond with capacity of 15,621.5 m3 can be increased to 25,012.2 m3 by deepening it to 3.0 m depth. It resulted an increase in net annual profit by Rs 5.00 lakh, 4.49 lakh, 4.07 lakh and 3.36 lakh at 50%, 60%, 70% and 80% probability of exceedence of rainfall and runoff respectively. Fish and vegetable production substantially contributed to the overall economics. The study has implications to serve as model to demonstrate rainwater-harvesting technologies for its large-scale adoption by the farmer’s of the region. The techno-economic feasibility indicated that the present rainfed uncultivated land could be brought to the level of irrigated agriculture by using water harvesting technology with practically no sign of resource degradation.