Diuron a urea herbicide
What is Diuron?
Diuron is a substitute urea herbicide, and Diuron is a systemic herbicide. The pure product is a colorless crystalline solid with a melting point of 158-159°C. It is easily soluble in hot alcohol and 5.3% in acetone at 27°C. It is slightly soluble in ethyl acetate, ethanol and hot benzene. Insoluble in water, the solubility in water is 42 ppm at 25°C. Low solubility in hydrocarbons. Stable to oxidation and hydrolysis.
Diuron physical and chemical properties
The herbicide Diuron is a colorless crystal with a melting point of 158°C to 159°C and a density of 1.48g/CIIl30. The solubility in water at 25°C is 42mg/L, and the solubility in organic solvents at 27°C is 53glL in acetone. Base stearate 1.4g/L, benzene 1.2g/L, slightly soluble in hydrocarbons. Stable in neutral liquid at room temperature, hydrolyzed when temperature rises, hydrolyzed in acid and alkali medium, decomposed at 180℃～190℃.
Diuron weed control characteristics
The herbicide Diuron is a selective herbicide, which is mainly absorbed through the roots of weeds, and can also be absorbed by stems and leaves, and kills weeds by inhibiting the photosynthesis of weeds. Generally, the medicated weeds begin to fade from the tip and edge of the leaves, and eventually the whole leaves wither. Diuron has no significant effect on seed germination and root system, and the duration of effect can generally reach 60 days.
Diuron application
The herbicide Diuron is used to control common weeds in non-cultivated areas and prevent weeds from respreading. Also used for weed control of asparagus, citrus, cotton, pineapple, sugar cane, temperate tree and shrub fruit.
Diuron, imuron and rituron are three commonly used substituted urea herbicides. Diuron is a systemic herbicide with a certain contact activity and can be absorbed by the roots and leaves of plants. Absorption is the main factor. After the weed root system absorbs the pesticide, it spreads to the leaves on the ground and spreads along the veins to the surroundings, inhibiting the Hill reaction of photosynthesis, causing the leaves to lose chlorosis, the tip and edge of the leaves fade, and then turn yellow and die. Diuron can be used as a selective herbicide at low doses and as a total herbicide at high doses.
Diuron is a substitute urea herbicide, which has systemic conduction effect and certain contact effect. The medicament is absorbed by plant roots or leaves and inhibits photosynthesis, resulting in chlorosis of leaves, discoloration of leaf tips and edges, and death of plants due to lack of nutrients. At low doses, Diuron can control weeds through potential difference and time difference selection. In high doses it becomes a total herbicide. Mainly used for cotton, soybean, tomato, tobacco, strawberry, grape, orchard, rubber plantation and other crops to control annual grass weeds and some broad-leaved weeds, such as barnyardgrass, crabgrass, foxtail, wild amaranth, sedge , quinoa, etc. For example, use 25% Diuron wettable powder 30-45g/100m2 in the cotton field before emergence, spray 7.5kg of water evenly on the soil surface, and the control effect is more than 90%; 15g/100m2, the control effect is more than 90%; fruit trees and tea gardens are at the peak of weed germination, use 25% wettable powder 30-37.5g/100m2, spray the soil surface with 5.3kg of water, and spray the soil after intertillage and weeding deal with.
How to use Diuron
Weeding in dry land: Apply after sowing and before emergence, use 0.25-0.4 kg of 25% wettable powder per mu, mix with 15-20 kg of moist fine soil, or mix 50-75 kg of water and evenly spray on the soil surface.
Weeding in paddy fields: 5-10 days after transplanting, use 300g-400g per mu, and prepare poisonous soil for spreading. For non-agricultural and pastoral areas, use 0.5-1 kg of medicine per mu, add 50-75 kg of water to spray or spray poisonous soil after rain when the grass is wet, and can kill annual or perennial weeds.
For cucumber fields, use 40-50 grams of 80% diuron wettable powder per 667 meters before the seedlings of cucumbers, add water to spray sugarcane before seeding, and use 80% diuron wettable powder 70 per 667 meters ~130g, spray on water. Phytotoxicity will occur when used alone at the seedling stage.
In the field, every 67 meters is treated with 80% diquat and 94 grams of stems and leaves, and the control effect on non-undergraduate weeds and peripheral leaf miscellaneous leather is 93%-99%. It is safe for garlic seedlings. From the comprehensive examination of cost and drug efficacy, the optimal dosage is 63 grams per 667 meters when it is popularized in a large area. If the medicine can be applied early, that is, in the two-leaf stage of the large weeds and the two-leaf stage of the grass weeds, the best effect can be achieved by using 47 grams per 67 meters.
The herbicide Diuron has a killing effect on wheat seedlings and is prohibited in wheat fields. In tea, mulberry, and orchards, it is advisable to use the poisonous soil method to avoid phytotoxicity.
Diuron has a strong contact effect on cotton leaves, so the pesticide must be applied to the soil surface, and it is not suitable to use Diuron after the cotton seedlings are unearthed.
In sandy soil, the dosage should be appropriately reduced compared with clay soil. It is not suitable for sandy paddy fields with leaking water.
The herbicide Diuron has strong lethality to the leaves of fruit trees and various crops, and the liquid should be prevented from drifting to the leaves of the crops. Peach trees are sensitive to diuron, so care should be taken when using it.
Instruments sprayed with diuron must be washed repeatedly with clean water.
When used alone, Diuron is not easily absorbed by the leaves of most plants, and a certain surfactant needs to be added to improve the absorption capacity of the leaves of plants.
The impact of diuron on the environment
1. Health hazards
Routes of entry: inhalation, ingestion, and percutaneous absorption.
Health Hazard: This product is a low toxicity herbicide. Mistake can be poisonous. Irritating to mucous membranes and upper respiratory tract.
2. Toxicological information and environmental behavior
Toxicity: It is poisonous.
Acute toxicity: LD503400mg/kg (rat oral); human oral 500mg/kg, the minimum lethal dose.
Subacute and chronic toxicity: oral administration of 5000ppm×90 days in rats did not cause death, but weight loss and red blood cell reduction.
Hazardous characteristics: Combustible in case of open flame and high heat. Decomposed by high heat, emitting toxic fumes.
Combustion (decomposition) products: carbon monoxide, carbon dioxide, nitrogen oxides, hydrogen chloride.
Diuron leakage emergency treatment
Isolate the leakage pollution area, and set warning signs around it. It is recommended that emergency personnel wear masks, goggles, and overalls. Sweep it up carefully, put it in a bag and transfer it to a safe place. It can also be washed with a large amount of water, and the diluted washing water can be put into the waste water system. In case of a large amount of leakage, collect and recycle or discard after harmless treatment.
Diuron protective measures
Respiratory system protection: Wear a gas mask during production operations or agricultural use. Wear a gas mask if necessary.
Eye Protection: Safety face shields may be used if necessary.
Body protection: Wear tight-sleeved overalls and long rubber shoes.
Hand Protection: Wear protective gloves if necessary.
Others: Smoking, eating and drinking are strictly prohibited at the work site. After work, shower and change clothes. Pay attention to personal hygiene.
Diuron first aid measures
Skin Contact: Wash thoroughly with soap and water. Seek medical attention.
Eye Contact: Hold eyelids open and rinse with running water for 15 minutes. Seek medical attention.
Inhalation: Get away from the scene to fresh air. Seek medical attention.
Ingestion: If swallowed by mistake, drink appropriate amount of warm water and induce vomiting. Seek medical attention.
Fire fighting methods: foam, dry powder, sand, water.
Precautions for Diuron
The herbicide Diuron should not be used on wheat and other crops that are prone to phytotoxicity. Cotton, tea, mulberry, fruit trees and other edible crops will be phytotoxic after being contaminated. When spraying the pesticide, care should be taken not to contaminate the edible crops. Caution and attention are required during use; the dosage can be appropriately reduced when the drug is used under high temperature conditions.
Diuron is used to control common weeds in non-cultivated areas and to prevent re-spread of weeds. The product is also used for weed control of asparagus, citrus, cotton, pineapple, sugar cane, temperate trees and shrub fruits.
Diuron Soil Environmental Behavior
Adsorption Behavior of Diuron in Soil
Adsorption model
The adsorption of Diuron by soil organic matter and soil particles, on the one hand, increases the residual amount of Diuron in the soil, and on the other hand, reduces its mobility and biological activity in the soil. The adsorption behavior of Diuron in soil is usually fitted by Freundlich adsorption model and linear adsorption model.
Freundlich adsorption model: Cs=Kf×Ce1/n; linear adsorption model: Cs=Kd×Ce. In the formula: Cs is the adsorption content of the soil to the test substance at the adsorption equilibrium (mg/kg); Ce is the concentration of the test substance in the water phase at the adsorption equilibrium (mg/L); Kf and Kd are the soil adsorption equilibrium constants; n is an empirical constant. Kf and Kd are important parameters for quantitatively judging the migration ability of Diuron in the environment. The larger the Kf and Kd values, the stronger the adsorption and fixation ability of Diuron in the soil, and the smaller the migration ability; on the contrary, the weaker the adsorption and fixation ability of Diuron in the soil, and the greater the migration ability. Many studies have reported the different Kf and Kd values of diuron in different soil environments, indicating that different soil properties have different effects on the adsorption and migration capabilities of diuron. the
Factors Affecting Diuron Adsorption
Soil Organic Matter Effects
Humic acid in soil organic matter contains a large number of active groups, such as hydroxyl, carboxyl, ammonium, methoxy, etc. The combination of Diuron produces adsorption. The content of soil organic matter is the main factor that determines the adsorption performance of soil to pesticides. The higher the organic matter content is, the more favorable the adsorption of pesticides is, and the larger the value of the adsorption model constant Kf is. Raise soil organic matter from 0.1% to 1%, and Kf from 25.3 to 500. Due to the differences in environmental conditions in different regions, even soils with similar physical and chemical properties may have large differences in Kf. Liu et al. found that the Koc value of Diuron in typical Chinese loess was 1537.49, and its Koc value in Czech Republic loess was 205, with a difference of nearly 7.5 times. The adsorption behavior of Diuron in soil is affected by soil properties and environmental conditions in different regions. Soil organic matter includes water-soluble and water-insoluble organic matter. Since the content of water-soluble organic matter in the soil is very small, the effect of organic matter type on soil adsorption capacity is not significant. However, when the soil moisture content is high, Diuron can be compared with The water-soluble organic matter in the soil interacts and migrates and transforms in the soil liquid phase. the
Effects of Soil pH
Soil pH is an important factor affecting the adsorption of pesticides. Soils with different acidity and alkalinity have different adsorption capacities for pesticides. Soil pH not only affects the decomposition of Diuron itself, but also affects the utilization of Diuron by microorganisms. Reducing the pH is beneficial to the absorption of Diuron by the soil. This is because the active groups in the soil are protonated, and the adsorption sites of Diuron molecules on the soil surface increase; on the contrary, increasing the pH of the soil will ionize the active groups in the soil. Diuron molecules compete with water molecules for adsorption sites on the soil surface, thereby reducing soil adsorption of Diuron. Ca2+ and Mg2+ can change the adsorption and weed control efficiency of Diuron. Soil pH has no significant effect on the adsorption of Diuron. On the one hand, the soil with higher organic matter content has a better buffer capacity for pH changes. On the other hand, Diuron is a urea herbicide that replaces urea. It is relatively stable, but it is prone to hydrolysis in acid and alkali media, which leads to a lower content of diuron in the solution under acid and alkali conditions. the
The effect of soil clay
Soil clay is the smallest and most active part of the soil, and its large specific surface area determines that its surface activity is stronger than that of sandy soil and loamy soil. Phongsakon et al. analyzed the physical and chemical properties of four kinds of pineapple planting soils and found that sandy loam had the lowest adsorption rate of diuron. The adsorption of diuron in three typical agricultural soils in Kenya showed that the soil clay content was positively correlated with the adsorption of diuron. A large number of adsorption sites on the surface of clay minerals have little effect on Diuron. This is because Diuron is a phenylurea herbicide and is a non-ionic compound. It is difficult to interact with water molecules at the adsorption sites of soil minerals in the water and soil system. Therefore, Diuron has higher mobility in this type of soil. Studies have shown that soil clay also affects the interaction between soil compounds and microorganisms, thereby affecting the adsorption of pesticides in soil. This is because the specific surface area of soil particles is different, and the adsorption capacity of degrading bacteria is different, so the adsorption capacity of pesticides is also different. At present, there are few studies on the adsorption of diuron-degrading bacteria in different soils, and it remains to be explored that the adsorption of diuron is affected by the same factors. the
The effect of soil temperature
Soil temperature has a significant impact on the change of Diuron Kf. In most cases, the adsorption capacity of soil for pesticides decreases with the increase of temperature. This is due to the fact that higher temperatures increase the water solubility of pesticides, thereby reducing the tendency of pesticides to adsorb in soil. For example, Liu et al. found that when the temperature increased from 298 K to 318 K, Kf values decreased from 14.34 to 4.99 (paddy soil), 33.57 to 11.16 (black soil), and 25.98 to 18.00 (yellow soil). Sun Hang et al. found through comparative experiments that the amount of adsorption of diuron on loess without adding biochar decreased as the temperature increased, and indicated that the process was an exothermic reaction. At the same time, the increase of temperature will reduce the adsorption sites of diuron on the soil surface. This is because a large amount of humus is adsorbed to the soil surface due to the increase of temperature. At this time, humus and diuron form competitive adsorption, which hinders the absorption of diuron Long adsorption in soil. the
The influence of the nature of the pesticide itself
The structure and properties of pesticides have certain influence on soil adsorption. 15 kinds of non-ionic pesticides were studied, and it was found that organic matter played a decisive role in the adsorption amount of non-ionic pesticides. The structure and properties of pesticides affect the distribution coefficient of pesticides in n-octanol/water phase. The larger the Kow value of pesticides, the easier it is to be adsorbed by soil. The soil adsorption tests for Diuron all show that Diuron can be adsorbed by soil organic matter through a distribution mechanism (Kow=648~747). In addition, the water solubility of pesticides also affects the adsorption of pesticides in soil. Diuron itself is insoluble in water, but its solubility in water is 42 mg/L at 25 °C. This property reduces the adsorption of Diuron on the surface of soil particles. quantity. Zhu Zhonglin et al. took 6 kinds of pesticides as research objects, andobtained the distribution coefficients of each pesticide in n-octanol/water phase as follows: methyl parathion>diuron>chlorotoluron>fluturon>vifuran>non-octanol Uron, andshowed that the partition coefficients are inversely related to their water solubility.
Movement of Diuron in the soil environment
No matter how diuron is applied, a small part will be lost to the surrounding environment such as water body and air, while most will settle on the soil surface. Soil is the main source and sink of diuron migration and transformation in cropland systems. Diuron's own physical and chemical properties and soil characteristics (such as soil organic matter, microorganisms) are the key factors affecting its environmental behavior in soil. Diuron interacts with soil organisms, soil particles and plants, and migrates and transforms in the soil environment through volatilization, leaching, photochemical degradation, biodegradation, etc.
volatile
Volatilization is an important way for pesticides to migrate in the soil environment. The volatility of pesticides directly affects their redistribution in the soil environment. Diuron has a long persistence in soil and sediment, and the loss rate of Diuron during volatilization is low. The volatilization of diuron on the soil surface was calculated by simulating the shape of the theoretical section, and the results showed that the total volatilization of diuron was only 2.63×10-5µg/m2. Even if the volatility of diuron is not significant, the concentration of diuron will accumulate under the condition of high concentration and continuous application, which will drift to pollute areas that are not related to weed control and harm non-target organisms. Air velocity, ambient temperature and soil properties are the main factors affecting the volatilization of diuron. High temperature is conducive to the absorption of herbicides by weeds, but if the temperature is too high, the sprayed diuron droplets evaporate rapidly, reducing the utilization rate of pesticides. The best time to apply Diuron in mulberry gardens is: in high temperature season, before 11:00 am or after 4:00 pm when it is sunny and windless, and between 10:00 am and 3:00 pm in low temperature season. In addition, soil moisture enhanced the adhesion of pesticides and reduced the volatilization loss of pesticides to a certain extent. When Diuron is used to treat soil, its efficacy is better in moist soil. the
leaching
Under certain conditions, Diuron can be directly dissolved in water and be adsorbed on the surface of solid fine particles in the soil, and be leached and lost from the soil by rainwater or irrigation water. There are many factors affecting the leaching loss of diuron in soil, such as climate, hydrology, soil physical and chemical properties, crop types, farming methods, etc. Xing Zebing et al. found that adding 1% Caragana biochar to the soil can have a significant adsorption effect on Diuron in the soil, thereby reducing the concentration of the pesticide residue in the leaching solution. Guzzella et al. used the leaching model (PELMO) to verify the mobility of Diuron in soil and water, and found that Diuron was only detected in the soil surface (0-10cm), while in soil pore water, it was detected at 20 and 40cm. Diuron dissolved in the soil seeps vertically downward with the water, seeps into the groundwater with the interstitial water and pollutes the environmental water body. Diuron has been detected in the groundwater, lakes, rivers and seawater of many countries and regions. The remnants of Turon. the
plant absorption
In the soil-plant system, Diuron can migrate to plants through plant roots or stems and leaves. A large number of studies have shown that Diuron can be detected in lettuce, rice straw, sugar cane, cotton and other crops. The migration behavior of diuron in different plants and organs will be significantly different. The enrichment ability of 4 plants to diuron was studied, and the results showed that the concentration of diuron in the roots of canna, japonica and rushes was significantly higher than that in the aerial parts (P<0.05), while the concentration in the roots of cattail was slightly higher than that in the aerial parts. From the safety point of view, the enrichment of Diuron in plants will cause Diuron in meat products.
soil animal absorption
There are many kinds of animals in the soil, with wide distribution and large numbers, and they are in close contact with the pesticides applied to the farmland. Extensive use of pesticides affects soil fauna community structure. Based on this, animals in the soil can be used as sensitive indicators of soil pollution to evaluate the degree of soil pollution. By comparing and analyzing the structure index and enrichment index of soil nematodes in different functional areas (phytophagy, bacteriophage, fungivory, omnivorous/carnivorous), the pollution degree of different functional areas can be obtained. Jiang Xin et al. used Collembola to track the toxicity of 3,4-dichloroaniline in the further degradation process, and showed that the ecotoxicity of 3,4-dichloroaniline was significantly higher than that of the parent compound diuron. At present, the interaction between soil mites and the soil environment has gradually attracted great attention from scholars at home and abroad. Due to the enrichment effect of soil animals, some effective pesticides enter the animal body, reducing the concentration of soil environmental pollutants and playing the role of "filtering" and "purification". the
Degradation of Diuron in soil
Degradation Pathway of Diuron in Soil
Usually, Diuron is mainly photolyzed and hydrolyzed in surface soil; Diuron is mainly degraded by microorganisms in deep soil. Now artificial techniques are commonly used to degrade Diuron in soil, such as adsorption method, electrochemical method, photocatalytic method, ultraviolet photooxidation method, etc. The degradation of diuron is affected by many factors, such as initial herbicide concentration, environmental conditions, microbial species, and degradation pathways. the
Hydrolysis of Diuron
The natural hydrolysis rate of diuron is very slow at 25°C, and its abiotic degradation in aqueous solution is an irreversible reaction, and the produced 3,4-dichloroaniline is the only hydrolysis product containing a benzene ring. In addition, OH-, H+ and phosphate buffers are effective catalysts for this reaction. Many researchers have found that organic and inorganic substances in the soil dissolved in the water phase can catalyze the chemical degradation of diuron. The decomposition mechanism of urea compounds involves the formation of isocyanic acid or isocyanate, followed by hydrolysis to amines and carbon dioxide. the
Photolysis
After Diuron enters the environment, whether it remains on the surface of plants or enters the atmosphere, water, and soil, it will be irradiated by sunlight to a certain extent and undergo photolysis. When Diuron undergoes photolysis, the ring-opening reaction of benzene and the oxidation reaction of alkyl groups occur, and at the same time, the chemical bonds such as C-C, CH, C-O, and C-N are broken by the action of light energy. Diuron is relatively stable under natural light, but affected by factors such as photosensitizers in the soil environment and soil pH, its photolysis rate in soil is accelerated. Studies have shown that in soil containing photosensitizers (TiO2, Fe2+), 100% decomposition of diuron can be achieved within 150 minutes under light. Yang Hai et al. used the xenon lamp/TiO2 system to photocatalytically degrade Diuron. The results showed that the photocatalytic degradation of Diuron conformed to the pseudo-first-order kinetics, and the neutral soil environment conditions were more conducive to the photocatalytic degradation of Diuron. The photocatalytic degradation rate of diuron increased with the increase of temperature. In addition, the photolysis rate of Diuron is also affected by other coexisting pesticides. The presence of pesticides such as Bromeuron, Meturon and Luguron can delay the photolysis of Diuron. The actual soil system is relatively complex, and there are many factors that affect the photolysis of diuron in soil, such as the physical and chemical properties of diuron, application concentration, soil type, soil moisture content, light source, etc.
Biodegradable
Microbial degradation is the main pathway for the degradation of Diuron in the soil environment. Generally, Diuron biodegrades mainly through co-metabolism and mineralization. At present, a large number of bacteria degrading Diuron have been screened and identified from the soil. The metabolism of microorganisms such as aerobic bacteria, fungi, and actinomycetes is the main form of Diuron transformation. Temperature, pH, ionase activity and other factors affect the biodegradation of diuron. Neurospora intertype DP8-1 isolated from sugarcane root can degrade 99% of diuron within 3 days at pH=7.2 and 32.6 ℃. Achromobacter xylosoxidans LX-C-06 was isolated from the soil, and the degradation effect of the strain was best when the temperature was 30 ℃ and pH=7.0 in the single factor test. Furthermore, in soil, the combined action of mixed microbial populations enhanced the degradation efficiency of diuron. the
The price of the herbicide Diuron
Usually, the price of the pesticide herbicide Diuron will be affected by raw materials, market environment, research and development costs, etc. If you want to know the latest price of the pesticide herbicide Diuron you need, please contact us to initiate an inquiry.
Tel: 13563082345 Email: sales@agripesticide.com
Supplier of the herbicide Diuron
Agripestcide is a professional agrochemical manufacturer, providing herbicides, insecticides, microbial fungicides, plant growth regulators and other products. If you are looking for Diuron Pesticide Herbicide, please feel free to contact us for latest price.