Abstract:
Efficiency of water use in canal command areas in Chhattisgarh is often quite low, estimated to be around 30%. Field to field irrigation is prevalent which not only reduces irrigation and nutrient efficiency, but also makes crop diversification difficult. Farmer's Participatory Action Research Programme was implemented in 4 villages of Dhamtari and Durg districts (two villages in each) of Chhattisgarh state, in the years 2007-08 to 2009-10. This programme was sponsored by Central Water Commission, Ministry of Water Resources, Government of India and implemented by Faculty of Agricultural Engineering, Indira Gandhi Krishi Vishwavidyalaya, Raipur. The objectives of the research conducted here include: 1. Conjunctive use of surface and groundwater through SFR and shallow dug wells. 2. Irrigation scheduling as per the ET requirement of crops and at critical crop growth stages. 3. Demo trial on full submergence, partial submergence and intermittent submergence at critical crop growth stages, and 4. Provision of drainage system in rice fields.
Canal irrigation water is quite unreliable in regard to its supply during critical crop growth stages. Therefore, construction of secondary reservoirs in the form of small farm reservoirs (SFR) in conjunction with shallow dug well to facilitate conjunctive use of surface and groundwater was found to be useful for assured water supply and to alienate water logging. This technology in the study area was found to increase the main product rice yield by
12.7 q ha' and that of by product yield by 21.0 q ha-'. Besides, some farmers by fish rearing, were able to get extra remunerations to the tune of Rs. 3000/- Drum sticks on pond bund and vegetables using SFR water provided farmers an additional remuneration around Rs. 9000/-. Thus, the land lost due to digging out SFR was not only compensated but promoted farmers to adopt crop diversification
Irrigation scheduling as per ET requirement of crops helped satisfactorily to develop seasonal irrigation plan/ schedule. Though theoretically, the rains at flowering and late reproductive phase were higher than ET requirement, either due to various water losses or the location of field at disadvantage position (tail enders), two irrigations each 50 mm at these stages are required to realize full potential of rice, particularly to late duration photosensitive rice varieties.
Three levels of submergence of rice fields were attempted in the study. Higher yield of rice main product was achieved in deep submergence 56.2-59.7 q ha' as compared to intermittent submergence and partial submergence, however, higher water use efficiency was observed in intermittent submergence (0.72-0.75 kg ha-1 m-3). The relative saving of water ranged from 1000 to 1500 m3 ha-' (12.3% to 16.1%) in intermittent submergence over deep submergence.
Drainage congestion as well as surface flooding in canal commands, pose serious threat to sustainable irrigation agriculture in Chhattisgarh. Appropriate drainage system incorporating preventive and curative measures were demonstrated to farmers. This drainage system had outlet in SFR which acts as sink to store the excess water that was further recycled as supplemental irrigation to rice during flowering and late reproductive stages. This drainage effluent stored in SFR was used by some farmers for fish rearing giving them extra remuneration. Provision of drainage system in rice fields increased rice yield by 4.9-5.7 q ha' and that of by product by 7.8-9.4 q ha-' worth Rs. 5200 ha-1.
