| Weedy rice, raised by natural selection and human intervention ofcommon wild rice and cultivated rice, was a middle typal rice with theircharacteristics. Observation on biological characteristics of weedy riceand study on control technique showed that weedy rice was mainlydistributed in0-5cm soil layer. Weedy rice had three germination peaks inthe field. The most suitable germination temperature was30to40℃. Theeffective accumulative temperature for germination was61.14℃.Themost suitable soil humidity for germination was between35and40%,where the plant height and tiller number were far higher thanconventional rice. Testing the loss rate of weedy rice under the differentdensity showed that the reduction of effective panicle number and filledgrains was the main factor causing yield loss of rice. Loss rate of rice wasincreased with the increasing density of weedy rice. The output of riceper mu would reduce more than150Kg when the number of weedy rice was five per0.25m2, and the total yield would harvest nothing when thenumber was sixty-fifth per0.25m2.Studying on integrated control of weedy rice showed that changedirect-seeding to mechanized transplanting, rotation with broad-leavedplants and deep tillage could help reduce17.16~28%of the ricegermination. The control effect would reach78.13%by using30%sofitEC200g per mu immediately after soil preparation. |
