The phenomenon of organic toxicity occurred on rice which appears frequently in the early phase of rice development and it appears more often in the autumn-winter, summer-autumn and early winter-spring, arable land of triple rice crops of Hau Giang due to farmer enlist sowing out in the field so fresh straw was buried in wetlands. These straw decomposed in anaerobic conditions produces low molecular weight organic acids such as oxalic acid, acetic acid, butyric acid, etc. That is caused by poisoning on rice plants. The research showed that triple farming of acid sulphate soil and alluvial soil which was done to determine the first treatment solution to reduce organic toxicity on rice. The research results showed that when fresh straw is buried in anaerobic digestion which has changed the pH, COD and organic acids in the soil. Fallow land betweentwo crops prolonged (about 2 - 4 weeks) with spraying preparations Trichoderma sp. and the first solution for phosphate fertilizers applied primer, lime, organic mineral fertilizers have the effect of reducing low molecular weight organic acids in arable land of triple rice cultivation, reduce organic toxicity in rice and increase rice yield and economic efficiency of rice production.