In direct-seeding rice fields, several herbicides are commonly used to control weeds effectively. According to the **China Pesticide Network**, here are some of the most widely applied options:
1. **Oxaxoline (Nongsi, Oxacillin)** is a selective pre- and post-emergence herbicide that works by contacting and being absorbed by weed shoots or seedlings. Once inside the plant, it accumulates in the growing tissues, inhibiting growth and causing tissue rot. It is most effective under sunlight conditions. After application, the herbicide spreads quickly on the water surface and is adsorbed into the soil, limiting downward movement and avoiding root absorption. It has a slow metabolism in the soil, making it ideal for controlling weeds like valerian, thousand gold, cow felt, sedge, water sedge, and others. For application, 25% oxaxoline can be used at 100–200 ml per acre, mixed with 45–60 kg of water. It can also be combined with other formulations like Funon or Marshette for better efficacy.
2. **Pyrazosulfuron-methyl (Cursor, Mercury)** is a sulfonylurea herbicide that is selectively absorbed by weed roots and translocated throughout the plant, stopping both stem and root growth. It is effective against annual and some perennial weeds such as ragweed, squash, and sedge. It should be applied 3–10 days after sowing, when weeds have 1.5 leaves. The recommended dose is 10–20 g of 10% wettable powder per acre. However, rice varieties may vary in their resistance to this herbicide, and care must be taken to avoid drift or runoff affecting nearby crops.
3. **Metham Sodium (Cycloclitoride)** is a systemic herbicide that moves through the xylem and phloem of weeds, preventing cell division and eventually killing the plant. It is most effective under water retention conditions due to its low solubility. It is safer for rice, especially when applied before the rice reaches the tillering stage. However, it is less effective in sandy or poorly drained soils. To enhance its effectiveness, it can be mixed with other herbicides like butachlor or quinclorac.
4. **Cyprosulfuron** is another selective herbicide that controls broadleaf and sedge weeds. It is absorbed through roots and leaves, stopping cell division and leading to weed death. It is suitable for both transplanting and direct-seeding rice fields. It is particularly effective against valerian and hard-to-control perennial weeds. Application is best done when weeds are in the 1.5–2.5 leaf stage, using 10–20 g of 10% wettable powder per acre.
5. **Bensulfuron-methyl (Hecao Danhe Cao Dan)** is a carbamate herbicide that targets weed germination and early growth. It is absorbed through roots and shoots, inhibiting the growth point of weeds. It is more effective on certain species like valerian and oxweed. Care must be taken to maintain proper water levels in the field to prevent phytotoxicity. It can be combined with other herbicides like chlorpyrifos or pyrazosulfuron-methyl, but not with 2,4-D, which reduces its effectiveness.
Additionally, **Jinqiu (10% Cyprosulfuron WP)** is registered for use in rice fields, offering good control of weeds up to the 2.5-leaf stage. It should be applied 2–15 days after sowing, with a water layer maintained for 5–7 days. It can be mixed with other herbicides like Marshette or Wo Da Zhuang to broaden the spectrum of control.
These herbicides offer farmers a range of options to manage weeds in direct-seeding rice fields, each with specific application guidelines and compatibility considerations. Proper use ensures both crop safety and effective weed control.
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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