Possible damage of herbicides to Golf Lawn and its Prevention

The selectivity of herbicides is relative and conditional, and any herbicide may harm the lawn if it is not used properly. Symptoms and causes of drug injury herbicide drug damage can be divided into acute and chronic drug damage. The acute drug damage was caused by contact herbicide, which showed fast speed, and the damaged lawn leaves showed brown spots, curl and discoloration. Chronic drug damage is caused by internal absorption of conductive herbicides, which is characterized by slow lawn growth, gradual yellowing and serious slow death. The reasons for herbicide damage to golf lawn are as follows: 1. Improper application: the amount of herbicide is calculated on the basis of the amount per unit area rather than the concentration. If you do not understand the application technology of herbicides, the wrong medicine or the wrong amount may hurt the lawn. The amount of spraying is not accurate and the uneven spraying is improper. When the lawn herbicide is sprayed with a spray machine, the spray has a strong impact on the lawn leaf surface, making the herbicide dipped in the lawn leaf surface, resulting in drug damage. If the temperature of the liquid in the container of the stirring sprayer exceeds 42 ℃, it may also hurt the lawn. two。 Improper maintenance and management: the application of most lawn herbicides such as lawn Ning 1, 38 and 42 requires irrigation for 15 to 20 minutes 40 minutes after spraying, which can minimize the absorption of herbicides on lawn leaves. If the land preparation is uneven before laying the lawn, spraying herbicides may hurt the lawn in low-lying areas. Spraying herbicides on lawns with high retained grass, thick withered grass and no mowing is easy to cause drug damage to the lawn. After spraying herbicide, cutting, drilling, piercing and so on will damage the root system of lawn and cause lawn yellowing. After spraying, the rolling machine makes the herbicide come into closer contact with the lawn leaf through the wheel, which increases the amount of herbicide absorption of the lawn, and at the same time makes the root zone of the lawn have poor air permeability and damage the lawn. If the player enters the green from where the herbicide has just been sprayed, it may hurt the green lawn. 3. Abnormal climate or poor lawn growth: high temperature, cold current, drought, hail, flooding and frost and other disastrous weather, resulting in abnormal lawn growth, spraying herbicides at this time, the herbicides absorbed by the lawn can not be degraded, easy to damage the lawn. The unstable temperature in early spring, the daily cooling of more than 12 ℃ or the application of herbicides in early spring frost attack can cause damage to the lawn. The application of herbicides when the temperature exceeds 33 ℃ may also cause drug damage. Second, the prevention and rescue of drug damage. The countermeasures to prevent possible drug damage are as follows: (1) weeding before bud. It is only necessary to use a constant amount of herbicides to prevent weeds before budding. if they are controlled after weed seedlings or when they are seriously damaged, it is necessary to increase the dosage of herbicides and increase the risk of herbicides causing drug damage to the lawn. (2) adhere to safe operation. Before spraying, the operators clearly define the application technology of herbicides, debug the spraying machinery, calculate the accurate dosage and operate according to the design. (3) maintain the strong lawn. The risk of drug damage caused by herbicides can be reduced by correctly maintaining and improving the ability of lawn to adapt to adverse environment. Low shearing, reducing withered grass layer, drilling holes and cutting regularly can improve the air permeability of lawn substrate, increase lawn root activity and reduce the side effects of herbicides on lawn. (4) low quantity and multiple applications. For the older weeds that exceed the appropriate period of control, the method should be applied continuously for many times in a low amount to avoid damage to the lawn caused by one-time application of high dosage. After repeated application of low dose, 60% to 70% of weeds were partially killed, and after 2 to 3 times, weeds were injured more and more seriously, which made weeds at a disadvantage in the competition with lawns, and their space was gradually occupied by lawns. (5) alternating mixed application. The combination of lawn herbicides with different action mechanisms can reduce the possible drug damage to the lawn. two。 Measures to prevent possible drug damage: (1) strictly control the dosage. Accurately test the walking speed of the machine or manual spray, check repeatedly before preparing the liquid, make sure it is correct, and then implement it to avoid errors. (2) ensure that the machinery is in good condition. Do not spray lawn herbicides with fogging machines. Before spraying with a large sprayer, it should be strictly overhauled to ensure that it is in good condition. The spray equipment was tested carefully, the operators were trained to spray with clean water, and the liquid was prepared by "twice dilution method". After dispensing, rinse the locomotive tires with clean water to prevent the wheels dipped in chemicals from crushing the lawn. Put an end to the dripping of machines and tools. Make a good mark to prevent re-spray and leakage. (3) avoid bad weather. When herbicides are used in transitional lawn belt in spring, they should be sprayed before the cold spell. In order to improve the ability to resist the harsh environment when the lawn turned green, the overwintering fertilizer with high proportion of potassium was applied from September to October to protect the lawn to survive the winter. Herbicides are prohibited during droughts, frosts and insect pests. Spray at a temperature of 15 ℃ to 33 ℃. When the temperature is higher than 33 ℃, the amount should be reduced properly. (4) strict control of management. When spraying soil treatment or herbicides with the effect of weeding before and after sprouting, watering for 15 to 20 minutes 40 minutes after spraying should be thoroughly watered. When some herbicides with both pre-bud soil treatment and post-seedling foliar effect were sprayed, not only 15 to 20 minutes after spraying, but also 5 to 6 minutes before spraying, the absorption of herbicides by lawn leaves could be reduced. Water the top of the slope "a small number of times" to prevent the potion from the top of the slope from being sprayed on the sensitive lawn or root of the tree below. Avoid fertilizing, spraying other pesticides and fungicides within a week when spraying herbicides. Low shearing should be done frequently to cultivate robust lawns with strong root activity. For the lawn which has been planted for a long time and the bedding layer is too thick, it is necessary to cut, punch, pierce, destroy the mat layer and increase the permeability of the lawn root system, which should be carried out one month before spraying herbicide to prevent drug damage. Avoid crushing after spraying. (5) to set up an isolation zone. When cross-sowing cold-season turfgrass such as perennial ryegrass in fairway, Lawn Ning No. 1 + 42 or Lawn Ning No. 1 + 18 can be sprayed at the same time or within 3 days successively. In order to prevent ryegrass from being sprayed on the fairway after irrigation, strip activated carbon strips 20 to 30 cm wide are sprinkled at the intersection of long grass area and fairway, industrial activated carbon is mixed well with 1 part of industrial activated carbon and 5 parts of sand, and two lines of ryegrass are spread with a sand spreader. It can also be sprinkled manually. It is especially important to spread at the junction above the fairway in the long grass area. 3. Rescue of possible drug damage: if herbicides cause slight drug damage to the lawn and the lawn turns yellow, the lawn root-promoting and green-keeping agent should be sprayed as soon as possible, with a dosage of 0.03 ml / m2 and 120 ml / m2 of water for 3 times. The sand mixed with industrial activated carbon can also be sprinkled on the damaged lawn as soon as possible to absorb the mistakenly sprayed herbicides to reduce the harm. When the drug damage is mild, a low concentration of foliar nitrogen fertilizer or potassium dihydrogen phosphate can be sprayed, with a concentration of 35% to 40% of the usual dosage. The key to successful rescue of lawn herbicides is to take remedial measures within 48 hours after misuse is found, and the earlier the time, the better the effect.