Insitu rice/wheat residue composting after combined harvest and ground water recharge

EASY COMPOSTING OF RICE/WHEAT RESIDUES AFTER COMBINED HARVESTING, WATER HARVESTING AND GROUND WATER RECHARGE
Asesh kumar Ghorai (Retired Principal Scientist, ICAR-CRIJAF) and Ankit Kumar Ghorai, Assistant Director of Agriculture (WBAS), Baghmundi Purulia
Rice/wheat residues left after combined harvesting can be converted to organic manures/compost under in situ condition using accelators. For one bigha land (0.134 hectare) a pit has to be dug at lowest spot of the field of dimension 5 m X 3 m X 1m. Only one percent of the total land has to be spent for this composting pit. This requires Rs. 2000 to dig the pit by JCB machine. Two man days are required to collect combined harvest rice/wheat residues from one bigha land. For fast decomposition of straw, in between two straw layers a mixture of 2 kg field soil, one Kg mustard cake, one kg N:P:K::10:26:26 and FYM, has to be added, as accelerator materials. The straw must be kept wet by irrigation (3-4) for its faster decomposition. Initially 5 kg FYM has to be spread at the floor of the pit for supply of decomposing organisms and earth worms etc. For summer and kharif rice fields no additional irrigation is required. Under waterlogged situation ammonium sulphate (1 kg per pit) should be applied to prevent methane formation. After 60 days spading is necessary for turning of lower material to upper side and vice-versa and proper aeration. For entry of sufficient oxygen up to bottom layer for well decomposition, perpendicular holes were made using bamboo poles ramming it on compost material with a weight material.
For this an experiment was done at ICAR-CRIJAF, Barrackpore, Kolkata. The field level demonstrations were made in collaboration with Asstt. Director of Agriculture, Chapra Block Nadia, Asstt. Director of Agriculture, Baghmundi, Purulia,Deptt. Agril. Govt. of WB (2020-2022). The manure formation process took 3-5 months. It was of dark colour and odorless.
During manure free period, usual field fishes (cat fish, walking fish, channa, puti, tilapia etc) will grow in these pits (holding 15000 litre water) for 3 months in Kharif season (July-Sept). In sandy and alluvial soil, these pits will enrich ground water through recharge of kharif rain (1400-1500 mm/year), nearly 1500 to 6000 litres per day depending on soil texture. It is still higher (12000 litre /day) where rainfall is around 3000 mm per year and soil is very porous ( North Bengal, India.
If an insitu pond of 12 m X 10 m x 1.5 m dimension is dugout in every one bigha land (1333 square meter or 1/3rd acre land) in its lowest corner, then it will harvest 1,80,000 litres of rain water in it for life saving irrigation under deficit rainfall, recharge 45-90 lakh litres water per year ( July to September, annual rain fall 1500 mm to 3000 mm) to the unconfined aquifer, help in small scale pisciculture and composting of crop residues like wheat, rice and mustard etc.
References:
1. Ghorai, A. K. 2020. In situ Enriched Compost Preparation from Rice and Wheat Straw using Tender Sunnhemp to Minimise Field Burning. Int.J.Curr.Microbiol.App.Sci. 9(09): 627-633.
doi: doi.org/10.20546/ijcmas.2020....
2. Asesh Kumar Ghorai (2023). Climate Resilient Rice Production, Intercropping in Rice, Alternate Crops, Insitu Water Harvestinig and Ground Water Recharge to Combat Deficit Rainfall. International Journal of Environment and Climate Change. 13(2): 75-82
DOI: 10.9734/IJECC/2023/v13i21656
3.Ghorai AK (2019). Ground water recharge and life saving irrigation potential of dug out ponds for in situ jute retting in rice .DOI: 10.13140/RG.2.2.16733.15848