Weed control techniques in rice direct seeding fields
1、 Mastering the regularity of weed emergence in rice direct seeding fields and selecting safe and efficient herbicides
1. The grass emergence time is long, with two obvious peaks. The germination of weeds in rice fields has two peaks, with the first peak being the main one, accounting for 60% of the total grass 10 to 20 days after sowing. The second peak is 25 to 40 days after sowing, accounting for 30 to 40%. The grass emergence before and after the two peaks is separated by 15 to 20 days.
2. Choose safe and efficient herbicides: "Direct seeding Feng" 35% Benazolin • Prochloraz, Kuaida Daoji (Pyrazolin • Dichloroquine) or Yangtian Yizheng/Yinheling (Benzyl • Dichloro) or Xiaozuofeng/Shabafenfeng (50% Sodium Dichloroquinolinate) produced by Jiangsu Kuaida Agrochemical.
2、 Weed control technology
According to the occurrence characteristics of weeds in live broadcast rice fields, chemical control should be taken as the main means, supplemented by agricultural measures, and a comprehensive prevention and control strategy of "early stage drug removal, mid-term water control, and later remediation" should be implemented: namely, the three principles of "one sealing, two killing, and three supplementing".
1. Direct seeding procedures of rice: seed soaking/seed mixing, leveling, top dressing, sowing (drill/manual), threshing, water harvesting, seed covering, irrigation, drainage of field surface water, manual spray of paired liquid medicine, moisture preservation, and water layer management.
2. "One seal": clear the furrow (very important: it is convenient for water entry and water conservation), cover the soil without dew seeds, and immediately water it. After 1-3 days after the border surface is dried without water, use the 35% Benazor • Propachlor WP100-120g of "Direct Seeding" to add 30-40kg of water to evenly spray (be sure to use a manual spray, not a mist spreader). After application, keep the furrow half full of water, and keep the border surface moist without water. Attention: The field should be leveled, moisturized without leakage or re spraying. If it rains after applying the medicine, quickly drain the water on the board area. Do not let the water from the applied field flow into the aquatic crop field, and be cautious of pesticide damage.
3. "Second kill": For the second peak of grass emergence and weeds that may remain after closure, chemical control can be carried out after the third leaf stage (two leaves and one heart) of the seedlings. During the occurrence of barnyard grass, 40-50g 30-45kg of "Shayifeng/Shayifeng" should be mixed with water and evenly spray. Do not use a mist eliminator. Stir thoroughly to dissolve and absorb, ensuring effectiveness (salt dissolution has a certain process). When using, it is possible to not drain water (the water layer should be shallow, and the water layer should not exceed 2-3 centimeters), but the dosage should be increased (the drainage effect is better). The drained fields should be drained and returned to the field 2 days after application, with a 3-5cm water layer for 3-5 days. For grass weeds such as barnyard grass and some mixed broad-leaved and sedge weeds in fields, Kuaida Daoji (50-60g of dichloropyrazine) or seedling field competition (60-80g of dichloropyrazine) can be selected.
Practice has proven that using appropriate drugs twice before and during the seedling stage after sowing can effectively control the occurrence and harm of weeds in direct seeding rice fields.
Medium term water control
Due to uneven sowing of direct seeding rice, weak and small seedlings in the early stage, and excessive sparse rice field space, weeds can easily grow too fast. Therefore, in the middle stage of direct seeding rice seedlings, good fertilizer and water management should be the main focus
Promote the early emergence of strong rice seedlings, achieve water control of grass, promote seedling suppression of grass, improve the effectiveness of pesticides, and avoid long-term water shortage that may cause grassland shortage.
Expert evaluation: Medium term water control can effectively improve preliminary chemical removal efficiency by 40-60%
For a few malignant weeds that are difficult to control, or for fields with poor control effectiveness and missing the appropriate control period, medication should be used for supplementary treatment, that is, after the 4-leaf stage of rice, according to different grass conditions, symptomatic treatment should be taken
For fields with a lot of barnyard grass and Qianjinzi, 40-50 grams of Mizuo Feng and Shazuo Feng (new dichloroquinoline acid) or 40-60 grams of Qiangao Quan (20% cyanofethyl) can be used per mu;
For fields dominated by broad-leaved weeds, 20-30g of 10% rice straw, 10-15g of 32% super fear or 20-30g of Shengfeng (10% pyrisulfuron methyl) were spray with water.
For fields with mixed monocotyledonous and dicotyledonous weeds, a mixture of 30% Yinhe Ling 60-80g or Kuaidadaoji 50-60g or more single herbicides can be used for weeding.
At the same time, combined with appropriate manual removal of weeds that are difficult to control, to achieve complete control of grass damage and achieve the goal of high yield of direct seeding rice.
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