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If performed correctly, thepractice of planting rice bybroadcasting rice seeds directlyinto unooded soil offers

several advantages over the usualpractice of transplanting seedlingsinto ooded elds. Farmers can savetime and labor, less water is requiredto establish the crop, and dry direct-

seeded rice suffers less from early-season drought. These are importantadvantages, especially in rainfed rice,and dry direct seeding is gainingpopularity in a number of areasacross Asia. According to the ThaiOfce of Agricultural Economics,around 38% of rainfed rice (reliant onrain with no irrigation infrastructure)in northeasternThailand in 2005was planted todry direct-seeded rice, andthis gure isgrowing.

by Yothin Konboon

Rice on the

Sometimes the best inventions are accidental. In northeastern Thailand, farmers

are adopting a weed-control method first taught to them by their animals.

The main problem withdirect-seeded rice is weed control.Transplanting seedlings gives ricea head start over weeds, and acontinuous layer of water suppressesweed growth. In northeasternThailand, the methods used tocontrol weeds differ from placeto place. Some farmers follow

ofcial agriculture departmentrecommendations while othersdevelop their own methods.

One of the most promisingfarmer-initiated controls is ricecutting, a method rst studied in1998 in deepwater rice by Thairesearcher Tawee Kuptkarnjanakul.Because deepwater rice is plantedvery early in the season, the periodbefore owering is long, resultingin excess growth of leaves andshoots. Farmers would cut theleaves just above the water surfaceprimarily to use as animal feed.

In northeastern Thailand, ricecutting began around 10 years ago,but not as a result of transfer fromdeepwater rice systems. Early-seasondrought is a regular occurrence inthe region and direct-seeded cropsfrequently suffer. When this occurs,some farmers give up on theircrop, leaving it for their animalsto graze. Over the years, farmers

have discovered that, when therains nally resume, the grazedcrop recovers well and ends upyielding a reasonable harvest.

After a few years of trial anderror, farmers in different areasdeveloped their own rice-cuttingmethods, which all include cuttingdown weeds as well as rice early

in the season. In some places,cutting is done primarily to reduceweed competition; in others, itis to improve soil fertility. Thepractice is spreading throughfarmer-to-farmer communication,media campaigns, and extensionworkers (the people responsiblefor technology dissemination).However, farmers and researchersunderstanding of the benets of ricecutting, and the conditions underwhich it succeeds or fails, is stillvery limited. Therefore, ThailandsUbon Ratchathani Rice ResearchCenter (URRC)with assistancefrom the Consortium for UnfavorableRice Environments (CURE), agroup of national and internationalinstitutions led by the InternationalRice Research Institutehasrecently conducted farm surveysto study and test this technology.

Farmers who practice rice cuttingsay that it boosts their rice yields

substantially, with some claimingthat it also improves soil fertility.They tend to use the method withtall, photosensitive rice varietiesthat is, varieties that ower inOctober independent of the sowingdateincluding Thailands famousjasmine rice. Once the rice crop hasbeen established, it is managed asusual until late Julyearly Augustwhen the rice cutting is conducted.This leaves around 50 days before

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18 Rice TodayJanuary-March 2009

CUTTING RICE with aswing grass mower canhelp control weeds.

yothin

konboon

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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 recoversufciently 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 eld should not risemuch higher than that. In eldswhere 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 where

the water level is low enough foroptimum cutting but sufcient 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 eld forsoil mulching and to recycle plantnutrients. Others use the cuttingsas animal feed. A few days aftercutting, farmers usually apply

fertilizer to boost crop growthand promote the decomposition ofresidues. By 1015 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 treatmentsricecutting in dry-seeded broadcast riceand the normal farmer practice ofdry-seeded broadcast ricewerecompared in 23 farmer elds. 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 other

benets 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 owering time.

In conclusion, rice cutting canhelp increase the productivity ofrainfed rice in northeastern Thailandand, importantly, can be integrated

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into the existing rice productionsystem. Especially in areas with poorsoils and severe weed problems, ricecutting offers new opportunities to

sustain and improve productivityand farmer livelihoods, as wellas to benet the environment.And, nally, rice cutting providesa great example of how farmersknowledge and modern research cancombine to stimulate new insightsinto rice production systems.

Dr. Konboon is an agronomistat URRC in Thailand.

A FARMER GROUP discusses the rice-cutting method.

THE AUTHORwith a swinggrass mower.