Herbicides have been used in China for more than 60 years. With the rapid promotion of simplified rice cultivation techniques, the full return of rice straw and the large-scale use of herbicides, the occurrence of weeds in rice fields is becoming more and more serious, and resistant weeds occur. The situation is also constantly increasing.
The resistance of weeds in rice fields is increasing, how should farmers respond effectively?
Before 2000, there was only one type of herbicide-resistant weeds in rice fields; before 2010, there were only four drug-resistant weeds; as of 2017, 14 rice-field weeds were resistant to 7 types of 10 herbicides. Liang Diyun, from the Institute of Pharmaceutical Machinery of the National Agricultural Technology Promotion Center, pointed out that the direct seeding fields in Hunan, Hubei, Anhui, Jiangxi, Jiangsu, Zhejiang and other provinces in the middle and lower reaches of the Yangtze River and Ningxia in the northwest are the hardest hit areas of rice field resistant weeds.
Drug-resistant weeds are a serious threat to rice yield and cause economic losses. How to prevent weeds in rice production areas in Northeast China? Where are the difficulties and pain points of rice field application in the Yangtze River Basin? At the “Third Farmland Weed Control Conference and Herbicide Development Summit Forumâ€, experts analyzed and combed the rice production areas in Northeast China and the Yangtze River Basin, and made suggestions for rice field weed control.
Rice field weeds are heavy, widely distributed, and resistant
The yield of glutinous rice in Northeast China accounts for 54.3% of the total production of glutinous rice in the country. The main weeds in rice fields are rice blast, awn mites, long awn carp, weedy rice, jiangxi, Lishihe, wild sage, rain long flower, wolf grass. , B. sylvestris, H. sylvestris, squid, sedge, sedge, broken sedge, and cotton.
Among the rice fields in Shanghai, valerian and Qianjin are the two weeds that have the greatest impact on the yield. The rice fields that have been broadcast live for many years have aggravated the trend; the ear leaves, water amaranth, clove, alfalfa, and double-spotted gar. There is also an upward trend in the occurrence of damage.
The dominant species of weeds in paddy fields in Zhejiang Province are Valerian, Thousand Gold, Double-spotted gar, Shaped sedge, Alternanthera philoxeroides, Aquilaria, Dwarf, Acacia, Cattle, and Clove.
Professor Ji Mingshan from the College of Plant Protection of Shenyang Agricultural University introduced that 9 kinds of weeds in the resistant rice growing areas in northeastern rice producing areas are resistant to 7 kinds of herbicides, namely, alfalfa, rice blast, rice cultivar, and long-lasting flower. Citrus, wild sage, valerian, cattle felt, firefly, etc., the occurrence of resistant weeds is heavy. Yao Xiaoming, head of the Department of Prevention and Control of Zhejiang Provincial Plant Protection and Quarantine Bureau, found that the degree of weed damage in rice fields was single-season rice field> continuous cropping late rice field> dry rice field. The damage of weeds in live field and throwing field was heavier than that in conventional transplanting fields. There are more grass species than conventional water nursery fields.
Rice resistant weed biotypes in Northeast China
The timing of weeding in rice fields is effective for the preparation of "grass"
Professor Ji Mingshan pointed out at the meeting that the control of weeds in paddy fields in Northeast China should be done in two aspects. One is the prevention and control of weeds in the seedbed: 60 grams of pyrazosulfuron per acre before the paving, used to control the triangular grass and broad Leaf grass and valerian; after covering the soil, spray Ding·Bing mixture to seal the weeding; in the three-leaf stage (7-10 days before transplanting), 120 grams of cyhalofop-butyl ester per acre, sprayed with stems and leaves.
The second is the prevention and control of Honda weeds. When the first peak of weeds was unearthed (7-10 days after soaking the fields), the rice blast, weedy rice, flat bark, wild sage, and watery cotton were weeded; weeds were unearthed. At the two peaks (10-15 days after transplanting), the rain-proof flowers, fire mites, eye vegetables, and small algae are controlled.
Common herbicides in rice fields
When is the application of medicine good? Is it necessary to seal the field in the early stage? Before the broadcast or after the broadcast? Do the rice field weeds first seal or kill first? How to deal with the weed control effect in rice fields to achieve the best? Wu Xiangwen's researcher proved through experiments that the control effect of "pre-sowing + post-emergence pre-emergence + rice growth in the early stage of blocking" in the direct seeding rice field reached 96.34% in the 9 days after the drug and reached 94.80% in the 15 days after the drug; Pre-sealing + stem and leaf treatment + rice growth in the early stage of blocking" 9 days after the drug control effect reached 97.56%, 15 days after the drug reached 95.40%; "post-emergence pre-emergence + rice growth before the blockade" 9 days after the drug control effect reached 86.45 %, the control effect reached 73.46% in the 15 days after the drug; the control effect was 81.46% 9 days after the "stem and leaf treatment + rice growth period", and the control effect was only 61.78% after 15 days. Similarly, researcher Wang Xianfeng of the Heilongjiang Provincial Agricultural Reclamation Bureau pointed out that the rice transplanting field is also dominated by soil closure, supplemented by post-emergence stem and leaf spray.
Yao Xiaoming, head of the Prevention and Control Section of the Zhejiang Provincial Plant Protection and Quarantine Bureau, said that the weeding mode of direct seeding rice fields in Zhejiang Province is mainly a pattern of “two kills and three supplementsâ€, “two seals and one supplementâ€, “one kill two supplements or one kill one supplementâ€. "One second kill three supplements" is sprayed with 36% bensulfame-propionamide 2-4 days after the live broadcast to keep the soil moist; 15-25 days after the live broadcast, supplement the stem and leaf herbicide according to the weed condition; After 30 days, the stem and leaf herbicide was supplemented according to the weed condition.
"Two seals and one supplement" is to apply 60% butachlor before sowing, and keep the shallow water in the field; the soil is kept moist for 2-4 days after the live broadcast, spraying 36% bensulfame-propionamide; 20-30 days after the live broadcast, According to the weeds, the stem and leaf herbicides are supplemented; "one kills two supplements or one kills one supplement" is applied 15-25 days after the live broadcast, spraying the stem and leaf herbicides, and applying the stem and leaf herbicide according to the weed conditions.
The drug is not good, maybe it is not avoiding the pain points of these drugs.
In the production process, the application of drugs is more blind, too dependent on the recommendation of pesticide dealers, and so on, and it is more serious. Unsystematic, unscientific medications lead to increased weed resistance, which in turn increases the vicious cycle of application.
Huang Jing, Marketing Department Director of Anhui Zhongbang Bioengineering Co., Ltd. pointed out that in the early rice area of ​​Dongting Lake, the pain points of closed medicine are mainly resistant to weeds such as resistant alfalfa and cattle felt, and the perennial weeds have poor sealing effect. The grass period is limited. Stem and leaf treatment of alfalfa is not complete, easy to relapse, subsequent germination is serious, a variety of agents mixed, medication biased, leading to rice susceptible to phytotoxicity.
In the early rice area of ​​Poyang Lake, the treatment was dominated by valerian and ragweed. The amount of alfalfa was large, and the period of herbage was long and irregular. The control of stem and leaf treatment of alfalfa was not complete, and the recurrence was more and the subsequent germination was serious. Valerian is equivalent to rice leaf age and is prone to phytotoxicity.
In the middle treatment of the middle-lying rice in the Hunan-Yunxi-Era, the weeds, the sedge, the sedge and the sedge were the main ones. The weeds were excreted for a long time, and the weeds continued to germinate after the closure. Shihe and so on can not be sealed; stem and leaf treatment of alfalfa is not thorough, recurrence is more, the subsequent germination of weeds is serious, and the effect of multiple remediation is not good.
Weeds such as scorpion grass and barley can not be sealed during the closed treatment of Sushenzhong rice water live field. Weeds still germinated after closure, and the conventional closed potting control period is limited; stem and leaf treatment of alfalfa is not complete and continues to germinate. There are many recurrences. Insects and water bamboo leaves are difficult to prevent, and resistance is not allowed to die.
In the closed-season rice field in the Yangtze-Huaihe River Basin, rice germination is fast, the closed medicinal plant is easy to injure seedlings, the number of weeds in the field is large, the period of grazing is long, and the film is unstable; when it is treated, it is difficult to prevent and cure, and it is easy to relapse. , weedy rice, rice Lishihe lack effective agents, it is difficult to control.
When the late rice in the Hunan-Yunnan region is closed, the temperature is high, the weeds are unearthed quickly, and the closure is not timely. Some perennial non-seed breeding weeds cannot be closed, and the alfalfa is difficult to be closed and controlled; when the stems and leaves are treated, the alfalfa and the thousand gold are inferior. There is a problem of antagonism in the medicament, and rice is susceptible to phytotoxicity.
Rice field application notes
In recent years, drug-resistant weeds have a wide distribution, many types, heavy degrees, and large losses. Weeding in paddy fields requires scientific use of herbicides, promotion of early treatment of herbicides, mixing of herbicides, addition of synergists, and research and development and promotion of new herbicides. According to practical experience, the head of the Department of Prevention and Control of Zhejiang Plant Protection and Quarantine Bureau Yao Xiaoming concluded that the rice field weeding should do the following 33 words:
Safety first, second effect;
Sealing the head, weeding active;
The field is level and focused on water conservation;
Focus on technology, flying defense is the trend.
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