How to carry out chemical weed control in rice fields

I. Chemical weed control in seedling fields

1. Fertile-bed dry-raised seedling beds. Fertile-bed dry-raised seedling beds have many weeds and great damage, so in control it is necessary to grasp the appropriate timing and comprehensively use 42% Xinye emulsifiable concentrate spray, and cover with film half an hour after spraying. For missed plots, after the three-leaf stage of the seedlings, water the bed surface fully, then use 45 g of 36% Daocaoling mixed with 50 kg of water for fine spraying.

2. Conventional rice seedling fields. For conventional rice seedling-raising plots, if weeds are mixed, the following methods can be used for control: (1) Within 4 days after sowing (germination must be promoted), use 30% Sofit mixed with water for fine spraying, and keep the seedling bed moist after application; (2) At the 2.5-leaf stage of the seedlings, after draining the field surface water, use 36% Daocaoling mixed with water for fine spraying, then rewater 24 hours after spraying, and maintain a 3-5 cm water layer for 5-7 days. If the seedling field is mainly infested with a single sedge and broadleaf weeds, after the 4-leaf stage of the seedlings, drain the seedling field water, and use 250 mL of 13% MCPA per mu mixed with 60 kg of water for fine spraying, then rewater 3-5 cm 36 hours after application, and keep water for 3-5 days.

II. Chemical weed control in main fields

1. Conventional transplanted rice main fields. For transplanted rice fields mixed with barnyardgrass, Cyperus difformis, and dwarf arrowhead, etc., use 35 g of 20% Youcaojing plus 10 g of 10% bensulfuron-methyl per mu; or 40-45 g (1.5 bags) of 20% Wanjiahuan plus 10 g of 10% bensulfuron-methyl. For transplanted main fields mainly infested with Cyperus difformis, wild water chestnut, and dwarf arrowhead, use 20-30 g of 10% bensulfuron-methyl per mu. For transplanted main fields mainly infested with barnyardgrass, use 35 g of 20% Youcaojing per mu. All the above formulations are mixed with 20 kg of moist fine soil per mu, applied with water retention within 4-6 days after transplanting and establishment, and after application keep a 1 cun water layer for 5 days.

2. Seedling-throwing fields and small-seedling transplanting fields. For fields mixed with barnyardgrass, sedges, and broadleaf weeds, use 30-40 g of 53% Paoyangxing; or 40-60 g of 50% Baicaokuojing. For fields mainly infested with broadleaf weeds, use 15 g of 10% bensulfuron-methyl wettable powder per mu, all applied 4-6 days after throwing (transplanting), mixed with 20 kg of moist fine soil per mu, and broadcast with water retention after the dew dries. Note that it must be done after the seedlings have established, and after application maintain a 3-5 cm water layer for 4-5 days; the water layer should not submerge the heart leaves. Acetochlor and its compound formulations are prohibited in seedling-throwing fields.

3. Water direct-seeded rice main fields. Use 120 mL of 30% Sofit per mu or 50 g of 36% Daocaoling per mu. Application method: For Sofit and Zhiboning, within 2-4 days after rice sowing, mix with 50 kg of water per mu for fine spraying, and keep the field surface moist after application. Rice fields using the above agents must have seeds soaked and germinated. For Daocaoling, at the 2-leaf-1-heart stage of the seedlings, drain the seedling field water, mix with 50 kg of water per mu for fine spraying, then rewater 36 hours after application and keep water for 5 days.

4. Wheat-intercropped rice main fields. For weed control in wheat-intercropped rice main fields, adopt the control strategy of "one sealing, two killing, three supplementing." "One sealing" means within the 2nd-4th day after intercropping rice, use 120 mL of 42% Xinye per mu mixed with 25 kg of poisoned soil, evenly broadcast when the soil is moist, then use a rope to push the wheat plants back and forth; "two killing" means after wheat harvest and seedling hardening, drain water, and use the special herbicide for wheat-intercropped rice fields, Yuguo Jinchu, mixed with water for spraying per mu, then rewater 36 hours after application and keep water for 5 days; "three supplementing" means at the late tillering stage of rice, according to the types of weeds in the field, select agents such as Qianjin and MCPA for supplemental control.