Studies On The Residue And Dynamic Degradation Of50%Anilofos Wettable Powder In Rice

Anilofos is an organic phosphorus absorption conduction selective herbicide developed by AgrEvo, Germany. It has been widely used because of its high efficiency, low toxicity and broad spectrum.The main weed control object of Anilofos is annual grass weeds and sedges. It directly perform in the weed surface, and can inhibit cell division and cell elongation of the weeds. Anilofos causes the leaves of the weeds to change brittle, thickened, and shorter. Under the effect of Anilofos, the leaves of the weeds are not easy to extract, ultimately resulting in the weeds stopping growing until withered. Therefore, Anilofos use in particular is in the germination of grass weed control better. As a suction conduction selective herbicide, with the advantages of broad-spectrum, high efficiency and low toxicity, Anilofos has been widely used in the insect pest control system in rice fields home and abroad, and can also be used in soybeans, wheat, sorghum, corn, fruit and vegetable system.This research uses gas chromatography with rice as the test crop, and on the basis of the pre-treated rice samples, founds the gas chromatography method of testing residual Anilofos in rice experimental field soil and rice fields of water and rice, brown rice and rice husk.Rice plants, soil and grain samples are extracted with acetonitrile and concentrated to near dry; then use acetone to constant volume on the machine; field water samples are liquid distributed with chloroform liquid, and concentrated in the40℃rotary evaporator to nearly dry; use acetone to constant volume; finally put into gas chromatographic.In this study, the minimum detectable amount is5.0×10-12g; the minimum detectable concentration:the paddy water is2.5×10-4mg/kg, paddy soil, rice plants, brown rice, rice husks are1.0×10-3mg/kg; for the actual added materials, the minimum detectable concentration in paddy soil, paddy water, rice husk, rice plants and brown rice are all0.025mg/kg.This research distributes Anilofos into0.025mg/kg,0.05mg/kg,0.50mg/kg three concentration levels and repeats for five times, recoveries were measured in accordance with the above pre-treatment methods and instrument conditions. The average Anilofos spiked recoveries in the paddy soil, paddy water, rice husk, rice plants and brown rice were respectively91.1-94.9%,86.1-94.0%,87.4-91.1%,89.5-92.6%and89.9-94.3%, relative standard deviations were respectively4.0-7.1%,2.9-3.8%,4.3-5.3%,3.4-5.1%and2.3-6.4%.This research takes a thorough view on50%Anilofos WP, conducting rice field experiments in Heilongjiang, Jilin and Hunan in2010-2011and in the laboratory tests residual Anilofos in soil in rice paddy water, rice plants, and in the brown rice and rice husk and the final residues are also studied.The digestion dynamic test results of this study indicate that:Anilofos wettable powder of50%Anilofos two years in Jilin Province, Heilongjiang Province and Hunan Province residue test half-life in paddy soil was1.0-8.3d, the half-life in paddy water1.0-2.0d, the half-life in the rice plant of0.1-4.6d. The degradation rate of Anilofos20d in the paddy soil was greater than80.8%, in the paddy water of7d was greater than92.8%, in the rice plant14d greater than78.6%. the above results indicate that the half-life of Anilofos was shorter in paddy soils, rice plants and paddy water, digestion rate. Therefore it can be characterized into the easily degradable pesticides.Using High dose of50%Anilofos WP63g/667m2, low dose42g/667m2, in the tillering stage of rice, mixed with20kg of fine soil evenly applicator, spray once. The test results of the final residue show that:in the two years in Heilongjiang, Jilin and Hunan Province, in harvest paddy soil, rice plants, brown rice and rice husk Anilofos residues were all lower than0.025mg/kg.The above studies have shown that this residual check test measurement method can effectively analyze Anilofos residues in rice samples fast and easily. With higher accuracy, precision and sensitivity of this assay method, the test methods conform topesticide residues in the test criteria requirements.In view that China has not yet developed or published MRL of Anilofos in rice, while Japan requires MRL of Anilofos in rice (brown rice) less than0.05mg/kg. take this as basis, according to the results of this study suggested that China’s development of MRL of Anilofos in rice (brown rice) is0.05mg/kg, and50%Anilofos WP usage on rice should not be higher than42g/667m2, with once spraying.