Fire Alarm Series,Fire Detector,WiFi Smoke Detector,Photoelectric Smoke Alarm Guangdong Isafenest Co.,Ltd. , https://www.isfenest.com
Live rice paddy field except for heavy seeding
In direct-seeded rice fields, weeds often emerge early and in large quantities, with multiple weed growth peaks. The first major peak typically occurs 5–7 days after sowing, dominated by grasses such as barnyardgrass and watergrass, which account for approximately 70% of the total weed population. This makes it crucial to focus on pre-emergence soil treatment when applying the "one-time kill, two-time control, three-time elimination" method. Understanding the weed emergence pattern is essential for effective management.
Weed development in direct-seeded rice can be categorized into two types: water-seeded and dry-seeded. In water-seeded fields, the first weed flush appears 5–7 days after planting, primarily consisting of barnyardgrass and watergrass. A second peak occurs around 15–20 days post-sowing, featuring broadleaf weeds and sedges, while a third peak appears 20–30 days later, mainly composed of grasses. Dry-seeded fields show similar patterns but also include additional weeds like crabgrass, ironweed, and waterpepper.
Soil closure treatment before seedling emergence is highly effective in preventing most weeds from establishing. Pre-emergence herbicides such as pendimethalin (Shi Tianbu) and pretilachlor are commonly used to target early-season weeds like barnyardgrass and watergrass, which make up a significant portion of the total weed biomass. These treatments are especially important for controlling species that persist for over 25 days after sowing.
After seedlings have emerged, a variety of herbicides can be applied depending on the type of weeds present. For grasses, options like quinclorac, bispyribac-sodium, and isoproturon are effective. For broadleaf weeds and sedges, herbicides such as bensulfuron-methyl and pyrazosulfuron-ethyl are recommended. Mixing different herbicides or using pre-formulated combinations like Xinye or Quick Removal can enhance efficacy and reduce resistance risk.
In dry-seeded rice fields, herbicides such as Shi Tianbu and Dingye EC are suitable for application after seeding. It’s important to maintain soil moisture for 5–7 days post-application without allowing standing water. After heavy rain, timely drainage is necessary to avoid phytotoxicity. In paddy fields, herbicides are usually applied 3–4 days after sowing, with formulations like pretilachlor and its mixtures being effective for germinated seeds.
Stem-and-leaf herbicide applications are used as a follow-up to control remaining weeds and manage the second weed peak. Timing is critical—application should occur after weed emergence, with specific herbicides chosen based on dominant weed species. For example, quinclorac is effective against barnyardgrass, while bispyribac-sodium works well for watergrass. Care must be taken to avoid overuse and ensure proper water levels during application.
For fields dominated by broadleaf weeds, combinations of herbicides like bensulfuron-methyl and 2,4-D may be used, but they should be applied with intervals to prevent antagonistic effects. Older or resistant weeds may require higher doses or alternative products like Weiba. In cases where sedges or other broad-leaved weeds are prevalent, specialized herbicides such as ethoxysulfuron or thiazolone can be employed.
By carefully timing and selecting the right herbicides, farmers can effectively manage weeds throughout the growing season, ensuring healthy rice development and high yields.