Detailed explanation of control techniques for sprangletop and barnyardgrass in paddy fields
Control techniques for sprangletop and barnyardgrass in rice
(Agricultural Wealth Network) Direct-seeded rice technology has been promoted in our city for nearly ten years, and its key technology is chemical weed control. Some farmers, unable to solve the weed problem, have had to plow and replow, while others have used double doses of quinclorac, spraying the rice until the seedlings became onion-tube-shaped while barnyardgrass still could not be killed. The main reason is that herbicides such as Zhibo Jing and Shabai Wang have been used year after year, and sprangletop and barnyardgrass have developed serious resistance to metolachlor and quinclorac. In addition, land preparation during direct seeding is extensive and water management in the seedling field is not done properly, so the control of sprangletop and barnyardgrass has become a difficult problem.
The Municipal Agricultural Materials General Company, together with relevant experts from the Municipal Agriculture Bureau, introduced a variety of herbicides and conducted many trials to address this problem, from which they summarized new agents and new techniques for controlling sprangletop and barnyardgrass in direct-seeded rice fields, seedling fields, and small-seedling transplanting fields. A brief introduction follows:
1. Omit the step of using Zhibo Jing (including Zhibo Qing, Ruinong, and other herbicides compounded from bensulfuron-methyl and metolachlor) for weed sealing 2-5 days after sowing, and instead use Daojie and Qianjin (10% cyhalofop-butyl) for control at about 15-18 days after sowing, at the two-leaf-one-heart stage of rice. Use 60-80 ml of Daojie and 40 ml of Qianjin per mu, mix with 30 kg of water, and spray evenly; after spraying, wait 24 hours before flooding. This method has a relatively high cost, but both safety and efficacy are very good, and many large grain-growing households in our city have already adopted this method.
2. For neglected older barnyardgrass, use 100-120 ml of Daojie per mu, mix with 30 kg of water, drain the field water, and then spray; flood 24 hours after treatment.
3. At the two-leaf-one-heart stage of rice, use 24 g of Lvheng 10% pyrazosulfuron-methyl plus 40-50 g of 50% quinclorac per mu, mix with 30-45 kg of water, and spray. It has significant control efficacy against barnyardgrass, broadleaf weeds, and Cyperaceae weeds. Note that pyrazosulfuron-methyl should be used rather than bensulfuron-methyl.
4. At the 3-5 leaf stage of rice and the 2-4 leaf stage of sprangletop, use 30-40 ml of 10% Baichu per mu, mix with 30 kg of water, drain the field water, and then spray; flood 24-48 hours after treatment. For 6-7 leaf barnyardgrass, 50-60 ml of 10% Baichu can be mixed with 30 kg of water and sprayed. When Baichu is used at high doses, special care must be taken not to spray repeatedly, as repeated spraying will injure the rice. This method costs less than using Daojie and Qianjin, is extremely effective against sprangletop and barnyardgrass, and is also effective against jointvetch and other grass weeds, but its safety is slightly poorer, so the application rate should be strictly controlled.
5. At 7-8 days after sowing rice, at the one-leaf-one-heart stage of the seedlings and the needle stage of barnyardgrass, use 10 g of Hanlesheng (10% flucetosulfuron) per mu and 35 ml of Guangmieling (36% clomazone), mix with 30-45 kg of water, and spray; it can control sprangletop, barnyardgrass, broadleaf weeds, and Cyperaceae weeds.
6. At the two-leaf-one-heart stage of rice, use 30 g of Hanlesheng (10% flucetosulfuron) per mu, mix with 45 kg of water, and spray; it can control barnyardgrass, broadleaf weeds, and Cyperaceae weeds at the two-leaf-one-heart stage.
The Municipal Agricultural Materials General Company, together with relevant experts from the Municipal Agriculture Bureau, introduced a variety of herbicides and conducted many trials to address this problem, from which they summarized new agents and new techniques for controlling sprangletop and barnyardgrass in direct-seeded rice fields, seedling fields, and small-seedling transplanting fields. A brief introduction follows:
1. Omit the step of using Zhibo Jing (including Zhibo Qing, Ruinong, and other herbicides compounded from bensulfuron-methyl and metolachlor) for weed sealing 2-5 days after sowing, and instead use Daojie and Qianjin (10% cyhalofop-butyl) for control at about 15-18 days after sowing, at the two-leaf-one-heart stage of rice. Use 60-80 ml of Daojie and 40 ml of Qianjin per mu, mix with 30 kg of water, and spray evenly; after spraying, wait 24 hours before flooding. This method has a relatively high cost, but both safety and efficacy are very good, and many large grain-growing households in our city have already adopted this method.
2. For neglected older barnyardgrass, use 100-120 ml of Daojie per mu, mix with 30 kg of water, drain the field water, and then spray; flood 24 hours after treatment.
3. At the two-leaf-one-heart stage of rice, use 24 g of Lvheng 10% pyrazosulfuron-methyl plus 40-50 g of 50% quinclorac per mu, mix with 30-45 kg of water, and spray. It has significant control efficacy against barnyardgrass, broadleaf weeds, and Cyperaceae weeds. Note that pyrazosulfuron-methyl should be used rather than bensulfuron-methyl.
4. At the 3-5 leaf stage of rice and the 2-4 leaf stage of sprangletop, use 30-40 ml of 10% Baichu per mu, mix with 30 kg of water, drain the field water, and then spray; flood 24-48 hours after treatment. For 6-7 leaf barnyardgrass, 50-60 ml of 10% Baichu can be mixed with 30 kg of water and sprayed. When Baichu is used at high doses, special care must be taken not to spray repeatedly, as repeated spraying will injure the rice. This method costs less than using Daojie and Qianjin, is extremely effective against sprangletop and barnyardgrass, and is also effective against jointvetch and other grass weeds, but its safety is slightly poorer, so the application rate should be strictly controlled.
5. At 7-8 days after sowing rice, at the one-leaf-one-heart stage of the seedlings and the needle stage of barnyardgrass, use 10 g of Hanlesheng (10% flucetosulfuron) per mu and 35 ml of Guangmieling (36% clomazone), mix with 30-45 kg of water, and spray; it can control sprangletop, barnyardgrass, broadleaf weeds, and Cyperaceae weeds.
6. At the two-leaf-one-heart stage of rice, use 30 g of Hanlesheng (10% flucetosulfuron) per mu, mix with 45 kg of water, and spray; it can control barnyardgrass, broadleaf weeds, and Cyperaceae weeds at the two-leaf-one-heart stage.