In direct-seeding rice fields, several herbicides are commonly used to manage weeds effectively. According to the China Pesticide Network, here are some of the most widely used options:
1. **Oxaxoline (Nongsi, Oxacillin)** is a selective pre- and post-emergence herbicide that works by contacting and being absorbed through weed shoots or seedlings. Once inside the plant, it accumulates in the growing parts, inhibiting growth and causing tissue decay. It is most effective under light conditions. After application, the herbicide quickly spreads on water surfaces and is adsorbed by the soil, limiting its downward movement and preventing root absorption. It is effective against various weeds like valerian, thousand gold, cow felt, and sedge. Application rates vary depending on the formulation—such as 25% emulsifiable concentrate at 70–150 ml per acre, mixed with 45–60 kg of water.
2. **Pyrazosulfuron-methyl** is a sulfonylurea herbicide that is rapidly absorbed by weed roots and transported throughout the plant, inhibiting both stem and root growth. It is effective against annual and some perennial weeds, including ragweed, sedge, and sorghum. The recommended dose is 10–20 g per acre of 10% wettable powder, applied 3–10 days after sowing. It’s safer for rice but can harm broad-leaved crops if misted or drained. Combining it with other herbicides like butachlor or quinclorac can enhance effectiveness.
3. **Metham Sodium (Cycloclitoride)** is a systemic herbicide that moves through the xylem and phloem, targeting the growth points of weeds. It is most effective under water-retentive conditions and has strong soil adsorption properties. It is ideal for controlling surface-growing weeds but less effective on deep-rooted species. When using this product, maintaining a 3–5 cm water layer for 5–7 days is crucial. It can be combined with other herbicides like bensulfuron-methyl for broader coverage.
4. **Cyprosulfuron** is another effective herbicide that controls broadleaf and sedge weeds. It is absorbed through roots and leaves, stopping cell division and eventually killing the plant. It is suitable for both transplanting and direct-seeding fields. It shows good control over valerian and hard-to-control perennial weeds. However, it is ineffective against weeds beyond the 3-leaf stage.
5. **Hecao Danhe Cao Dan (Carbaryl-based herbicide)** is a selective soil treatment herbicide that is absorbed by weed roots and shoots, particularly affecting young growth. It prevents germination and early-stage weed development. It is more effective on valerian and certain sedges than on three-leaf-stage sedges. Maintaining proper moisture is essential to avoid phytotoxicity. It can be combined with other herbicides like bensulfuron-methyl or pyrazosulfuron-methyl, but not with 2,4-D.
Additionally, **Jinqiu (10% Cyprosulfuron Wettable Powder)** is registered for use in rice fields. It should be applied within 2–15 days after sowing, when weeds are in the 1.5–2.5 leaf stage. The recommended rate is 10–20 g per acre. Keeping a 3–5 cm water layer for 5–7 days ensures optimal performance. It can be mixed with other herbicides like Marshette or Wo Da Zhuang to improve efficacy.
These herbicides offer a range of options for managing weeds in direct-seeding rice fields, each with specific application guidelines and compatibility considerations. Always follow label instructions to ensure safety and effectiveness.
Wiper Seals
Wiper Seals are a type of mechanical seal commonly used to protect piston rods and pistons in hydraulic and pneumatic equipment. The main function of Wiper Seals is to prevent dust, dirt, and other impurities from entering the interior of the equipment, thereby protecting the sealing performance of the piston rod and piston, and extending the service life of the equipment.
Wiper Seals are typically made of elastic materials such as polyurethane, nitrile rubber, fluororubber, etc. These materials have excellent wear resistance and chemical resistance, and can maintain stable performance in various harsh environments.
Wiper Seals are typically divided into two types: unidirectional and bidirectional. Unidirectional Wiper Seals can only prevent dirt and impurities from entering the device from one direction, while bidirectional Wiper Seals can simultaneously prevent dirt and impurities from entering the device from both directions.
Wiper Seals can also be customized according to different application requirements. For example, for high-speed rotating devices, special Wiper Seals can be used to ensure that they do not generate excessive heat and friction during high-speed rotation. For equipment used in harsh environments, special materials such as corrosion-resistant, high-temperature resistant, and low-temperature resistant Wiper Seals can be used.
In summary, Wiper Seals are in dispensable mechanical seals in hydraulic and pneumatic equipment, and their excellent performance and reliable sealing performance provide important guarantees for the normal operation of the equipment. If you need a Wiper Seals product, you can contact a professional seal manufacturer to customize the appropriate Wiper Seals for your device according to your specific needs.
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