control weed occurrence in water direct seeding paddy fields effectively

  The seeding procedure of water direct seeding rice is as follows: rotating tillage with upper water and leveling with water, drainage seeding and valley collapse after slurry water sinking, and application of pesticides for soil sealing treatment 2-4 days after sowing. Because of water preparation, the field is easy to be leveled, the soil in the tillage layer is soft and the soil is wet, which is conducive to the growth of whole seedlings and seedlings. Attention should be paid to keeping the soil moist after sowing. On the one hand, it is conducive to the efficacy of closed herbicides.   On the other hand, it will not cause rice seeds to "sprout" because of drought and water loss, and improve the emergence rate and seedling rate.

  There are many weeding peaks in direct seeding paddy field. Generally, the first weeding peak occurs 5-7 days after rice sowing, mainly barnyard grass, thousand gold seeds and Echinochloa; the second weeding peak occurs 15-20 days after sowing, mainly Cyperaceae weeds and broad-leaved weeds, such as heterotypic cyperus, paddy field weeds, knotweeds and duck tongue weeds; the third weeding peak occurs in some fields 20-30 days after sowing, mainly fluorescent. Cyperus matsutake and sedge are the main species, and some broad-leaved weeds are also found. Because there are many weeding peaks in water direct seeding paddy field, it is advisable to adopt there steps to control weeds in water direct seeding paddy field, so as to effectively control weed occurrence in water direct seeding paddy field.

  First: Soil sealing treatment was carried out 2 to 4 days after rice sowing. Most of the direct-seeding paddy fields sow germination-promoting valleys, and propachlor and its mixtures with bensulfuron-methyl, pyrimsulfuron-methyl and chloropyrimsulfuron-methyl are suitable for soil sealing treatment before seedling. Prochlor products registered for direct-seeding paddy fields should be selected in direct-seeding paddy fields. These products can improve the safety of rice by adding safety agents. In case of continuous rainfall after application of pesticides, drainage should be done in time so as not to cause pesticide damage to rice caused by prolonged accumulation of water on the field surface.

  Second: Soil blockade was carried out at 2-3 leaf stage of rice combined with early stem and leaf treatment after seedling. Dichloroquinoline acid, pentafluorosulfuron, pyrimsulfuron-methyl, bensulfuron-methyl and their mixtures can be used as both soil sealing treatment and stem-leaf treatment, or they can be mixed with propachlor and its mixtures.

  Third: After two previous weeding, suitable stem and leaf treatments can be selected according to the situation of residual weeds in the field. Cyhalothrin and oxazolamide can be used to control Gramineae weeds such as tangerine, barnyard grass and Thousand Golden seeds. Cyhalothrin ester had no requirement for rice seedling age. The optimum application period was around 3-leaf stage of weeds. The mixture of Cyhalothrin and sulfonylurea herbicides such as pyrimsulfuron-methyl and bensulfuron-methyl can produce antagonism and reduce its control effect on gramineous weeds. Appropriate increase of the dosage of Cyhalothrin can alleviate this adverse effect. It can not be mixed with zoxanone and 2-methyl-4-chloride to avoid affecting the control effect on gramineous weeds and reducing the safety to rice. Oxazole-oxaloxamide is suitable for rice from 2-leaf stage to jointing stage. It can be mixed with cyhalothrin and methamphetamine with reliable quality. For the control of broad-leaved weeds and sedge, 2-methyl-4-chloride, methazone and zoxanone can be used, and attention should be paid to avoiding high temperature at noon. 2-methyl-4-chlorine should be applied from the 4th leaf stage to the pre-jointing stage of rice. Azoxanone should be applied from the 2nd leaf stage to the jointing stage of rice, and attention should be paid to the second dilution. The dosage should not be too large and should not be mixed with emulsifiable preparations or other formulations. Otherwise, the dispersion of Azoxanone in the solution will be easily affected, which will aggravate the contact toxicity of Azoxanone. Chlorofluoropyroxyacetic acid is only effective for broad-leaved weeds, but not for sedge. It should be applied from 4-leaf stage to pre-booting stage, and the dosage of chlorofluoropyroxyacetic acid should not be too large at seedling age. In the field with high occurrence of resistant barnyard grass and Echinochloa chinensis, Lingsco chlorofluoropyridine ester can be used to control the disease, and a variety of broad-leaved weeds and sedges can also be controlled. Pentafluorosulfonamide can control barnyard grass, annual sedge and broad-leaved weeds, and can be applied in areas where barnyard grass is not resistant to the drug.