The flower of walnut seedling is wind-pollinated. The distance of pollen dissemination is related to the wind speed, terrain, etc. Within a certain distance, the amount of pollen dispersal increases with the increase of wind speed, but decreases with the increase of distance. According to research reports, the best pollination distance should be within 100 meters of the pollination tree. Beyond 300 meters, almost no pollination can occur, and at this time artificial pollination is needed. The lifespan of pollen under natural conditions is only about 5 days. According to measurements, the vitality of freshly dispersed pollen is as high as 90%, which drops to 70% after one day. Under indoor conditions, all pollen loses activity after 6 days. Even under refrigerator storage conditions, the vitality of pollen collected 12 days ago drops below 20%. During the day, the best time for pollinating female flowers is between 9-10 am. The effect is closely related to weather conditions and flowering situations. Years of experience have proven that those with short female flower periods and neat blooming have higher fruit setting rates; otherwise, they are lower. According to surveys, those with female flower periods of 5-7 days have fruit setting rates as high as 80-90%, those of 8-11 days have fruit setting rates below 70%, and those of 12 days have fruit setting rates of only 36.9%. If low temperatures and rainy weather occur during the flowering period, it will significantly affect normal pollination and fertilization activities, reducing the fruit setting rate. New walnut orchards need to be equipped with pollination varieties, with a ratio of 3:1 or 4:1 to the main cultivated varieties, or planted in alternate rows or alternate plants. Planting generally involves digging holes in the range of 50-80 cm, depending on the soil quality. When digging the hole, place the topsoil on the left and the subsoil on the right, adding fertilizer to the topsoil, such as fermented chicken manure. Cultivation cannot use chemical fertilizers (easy to burn roots). Generally, the holes are dug 1-2 months in advance, which helps the land mature. At this time, fill the bottom with the topsoil mixed with fertilizer and flip the subsoil to the top. The planting depth follows the original soil mark of the original seedling. Too shallow planting is not drought-resistant, and too deep planting does not promote seedling growth. Based on our base's years of cultivation experience, remember the walnut planting method: three burials, two stomping, and one lifting of the seedling. These details are very beneficial for the growth of walnut trees. Smoke method: When the minimum humidity is no less than -2 degrees Celsius, smoke can be produced in the orchard. Smoking reduces the radiation dissipation of soil heat. At the same time, smoke particles absorb moisture, causing water vapor to condense into liquid and release heat, raising the temperature. The common smoking method uses flammable dry grass, shavings, sorghum stalks, etc., layered alternately with damp fallen leaves, grass roots, sawdust, etc., covered with a layer of soil outside, with a wooden stick inserted in the middle for easy ignition and smoke production. The smoke stacks should be distributed around and inside the orchard, denser on the upwind side so that the smoke quickly covers the entire orchard. The size of the smoke stack is generally no more than 1 meter high. When frost is forecasted by local meteorological services, fire can be ignited to produce smoke when the temperature drops to 5 degrees. Artificial rain, spraying water, or foliar fertilization: Use artificial rain equipment or spray equipment to spray water on the tree body when frost comes, releasing latent heat when water cools and solidifies, increasing humidity, and reducing frost damage. Foliar fertilization can increase cell concentration, achieving better results. Strengthen comprehensive cultivation management technology: Enhancing tree vigor can improve frost resistance. After frost damage occurs, active measures should be taken to strengthen management to ensure yield and tree recovery. Artificial pollination should be carried out for late-opening flowers to increase the fruit setting rate and ensure a certain yield for the year. After young branches and leaves are frozen, new branches and leaves will still grow, promoting their healthy growth to restore tree vigor. To buy high-quality walnut seedlings, cherry seedlings, fruit tree seedlings, and fruit tree planting, visit Xinyuan Seedling Base http://www.xytymm.cn/.