How much water does rice need? - adron.sr

yothin konboonA FARMER GROUP discusses the rice-cutting method.the development of the panicle (thepanicle bears the grain later on). Thecutting time is crucial for success.Cut too early and it has no effect onweed and rice growth because theplants are too small. Cut too lateand the rice plant may not recoversufficiently to produce a good yield.Using a swing grass mower (seephoto, opposite), farmers cut riceand weeds at a height of around 5cm above ground. Thus, the waterlevel in the field should not risemuch higher than that. In fieldswhere deeper water levels occurregularly, the water will suppressweeds adequately without the needfor cutting. If the rice plants arecut much higher than 5 cm, thestimulating effect on the number ofstems (which carry panicles later)does not occur. Therefore, the methodworks best in middle terraces wherethe water level is low enough foroptimum cutting but sufficient toallow good crop growth after cutting.The practice is not recommendedon upper and lower terraces.The uses of the cuttings differfrom farm to farm. Some farmersleave the residues in the field forsoil mulching and to recycle plantnutrients. Others use the cuttingsas animal feed. A few days aftercutting, farmers usually applyfertilizer to boost crop growthand promote the decomposition ofresidues. By 10–15 days after cutting,the rice crop has regrown to thesame height as before the cutting.To evaluate the effect of ricecutting, URRC conducted on-farmtrials in 2007-08, targeting farmerswho had not previously practicedrice cutting. Two treatments—ricecutting in dry-seeded broadcast riceand the normal farmer practice ofdry-seeded broadcast rice—werecompared in 23 farmer fields. Initialresults showed that rice cuttingwas effective in suppressing weedsand average rice yields improved by12% over the no-cutting treatment.However, variation was considerablefrom farm to farm and somefarmers had no yield increase.Discussions among farmers andresearchers revealed several otherbenefits aside from increased yield:reduced weed competition alsolowered the labor needs for weeding,fewer pest problems occurred becauseof a less dense and more aeratedcrop canopy, and harvesting waseasier because of the more uniformplant height and flowering time.In conclusion, rice cutting canhelp increase the productivity ofrainfed rice in northeastern Thailandand, importantly, can be integratedTHE AUTHORwith a swinggrass mower.into the existing rice productionsystem. Especially in areas with poorsoils and severe weed problems, ricecutting offers new opportunities tosustain and improve productivityand farmer livelihoods, as wellas to benefit the environment.And, finally, rice cutting providesa great example of how farmers’knowledge and modern research cancombine to stimulate new insightsinto rice production systems.Dr. Konboon is an agronomistat URRC in Thailand.prajuab duangpakdeeRice Today January-March 2009 19