Measures to prevent Frost in flowering period of Walnut Fruit trees

   1. The selection of suitable garden plots and varieties should refer to the results of local agroclimatic regionalization, make a reasonable industrial layout, and select favorable topography that is not conducive to air-conditioning accumulation to avoid the harm of low temperature and frost. In general, cold air in valleys or depressions is easy to gather, which often causes frost, so we should try to avoid building gardens in low-injection areas, but should choose gentle slopes and build good orchard windbreaks.

At the same time,    should increase the investment in anti-freezing research, cultivate cold-resistant, cold-tolerant and high-yield walnut varieties, and expand the planting area. The selection of varieties with strong frost resistance, late florescence and short growth period is an important way to avoid frost. In addition, the application of organic fertilizer, good control of diseases and insect pests and reasonable load can enhance the tree potential, improve the nutrition level of the tree, and thus improve the cold resistance.

   2. Smoke this is a traditional measure to prevent frost. After smoking, a smoke screen can be formed around the tree, which contains a large amount of carbon dioxide and water vapor, which can effectively prevent the loss of heat on the garden, prevent the temperature in the garden from falling, and make the tree in a stable air temperature environment; at the same time, smoke particles absorb moisture, make water vapor condense into liquid and release latent heat, thus preventing the formation of frost.

The materials commonly used as smoke stacks of    are mainly crop straw, litter and weeds. These materials should have a certain degree of humidity, and the thin soil can also be removed from the straw to set aside an ignition and smoke outlet. According to the time of frost forecast by the meteorological department, the walnut orchard can be ignited and smoked to protect the walnut orchard from frost damage. Generally, the material for each cigarette stack is 3050 kg, and 4 smoke piles are available for every 667 square meters. This method has a large amount of smoke, simple and easy, and the effect is good. Usually frost occurs at 3: 5 in the morning. During the walnut blossom period, you should listen carefully to the weather forecast and set up smoke piles in advance. Special personnel are assigned to be on duty to observe the temperature, especially the temperature change in the low injection area. When the temperature drops to-1.5 °C and continues to decline, cigarettes can be lit. Through smoking, the temperature of the orchard can be increased by more than 2 ℃ and frost can be prevented.

   can also be smoked with a special fumigant, which is mixed with 20% ammonium nitrate, 50% sawdust, 10% waste diesel oil and 10% fine pulverized coal, rolled up into a cylinder with waste newspaper for easy to carry, and should be prepared in sufficient quantity so that it can be smoked continuously. When the temperature drops to 2 ℃, the prepared fumigant is ignited and evenly distributed in the orchard, which can effectively reduce or prevent the harm of late frost.

   3. Irrigation on the ground and before sprouting can reduce the ground temperature, postpone germination and avoid frost damage. Before the arrival of the frost, in the areas with better water conservancy conditions, you can irrigate the ground in time according to the weather forecast, or spray water directly to the trees. The specific heat of water is high. When the air temperature is lower than 0 ℃, the air humidity of the walnut orchard can be increased and the cooling rate of the park can be delayed by irrigation or spraying. After spraying water, the tree can also delay the flowering and slow down the damage degree of freezing injury. 3% zero. The effect of 5% sucrose solution is better.

   when the salt solution is formed by salt in the water, the freezing point temperature decreases. When the frost occurs, the trees spray salt water to prevent the water vapor in the air from frosting on the branches and avoid the harm of frost to the branches and flower buds. According to the experiment, from dormancy to germination, the concentration of saline solution is 0. 5%. 5% 2%, the concentration can be high in the dormant period and low in the budding period, otherwise it is easy to cause salt damage.

   4, trunk whitening and branch lime milk whitening in winter can reduce the radiation heat absorbed by the aboveground part of the tree, make the tree temperature rise slowly, delay the sprouting and flowering period, avoid the harm of frost, and have the effects of antibacterial, killing eggs and larvae, and preventing sunburn. Preparation method of whitening agent: 5 kg of quicklime, 0.5 kg of sulfur and 0. 5 kg of rapeseed oil. 1 kg, salt 0. 5%. 25kg, 20kg of water, stir well and brush the tree trunk.

   combined with trunk whitening, spray lime milk on tree branches, can effectively reflect sunlight, reduce tree temperature, delay flowering for 5-6 days, so as to avoid frost. The formula of lime milk is 50 kg of water and 10 kg of quicklime, stirring evenly, and then adding 100 grams of diesel oil as adhesive to increase the adsorption on the branches.

   5. Covering trees this method is more suitable for sporadic young walnut trees. That is, before the arrival of the frost, cover the young trees with grass curtains and plastic sheeting or bind the grass to the young trees to avoid the harm of late frost. For primary fruit orchards and orchards that are difficult to cover, grass barriers can be erected around the orchards and rows to prevent external cold attacks and retain the distributed ground temperature.

   6. Spray 0. 0 on the crown before sprouting with chemicals. 0.5% potassium acetate solution, 0.5% calcium chloride solution during germination and 200 times high ester film before flowering can delay the flowering period of walnut trees by 5 to 7 days and effectively prevent the harm of late frost during flowering. Spraying antifreeze and fruit protectant on walnut trees before frost can also prevent the harm of low temperature frost and protect flowers and fruits.