Water-retaining agent, commonly known as super absorbent resin, is a grid-like polymer material with strong hydrophilic groups. It can not only absorb hundreds of times of non-ionized water, but also absorb it when the environment is dry. The water in the material is released and plays the role of drought resistance, water retention and soil improvement.

　　1 The function of water retaining agent in drought-resistant afforestation

The main function of 　　 water retaining agent in drought-resistant afforestation is embodied in the following aspects: increasing soil moisture content. The water-retaining agent has a strong water absorption capacity, and it is mixed in the soil to form water-absorbing soil. The saturated water content of the soil is much higher than that of ordinary soil, so the effective water consumption of the soil mouth is also increasing. In addition, the water retaining agent can maintain a period of time after absorbing enough water, so the trees can be continuously absorbed and utilized; the water retaining agent can promote the growth of seedlings, and the seedling delay period of the water retaining agent is shorter, because the water retaining agent can maintain the moisture of the roots of the seedlings , Improve the soil in which it grows. Of course, attention should be paid to the amount of use during the application process, so as to avoid excessive soil water content and increase ground temperature, which will adversely affect the growth and development of seedlings; it can increase the survival rate of afforestation. The water-retaining agent has strong water absorption and can quickly absorb water to form a hydrogel, which plays a role in water retention. After the seedling roots are treated with the water-retaining agent, a layer of water-absorbing gel will adhere to the root surface. When the soil is short of water, it will absorb water. The gel will release water slowly, and the roots of the seedlings can be absorbed and utilized. When the soil moisture is full, the water-retaining agent can absorb water and save for later use, so it can maintain the root water balance of the seedlings for a longer time and improve the survival rate of afforestation.

　　2 Afforestation application technology of water retaining agent

　　 water retaining agent is not only suitable for transplanting ordinary seedlings, but also for transplanting large seedlings. First apply sufficient water-retaining agent in the tree-planting hole. Before transplanting large seedlings, it also uses large-particle water-retaining agent. The water-retaining agent reaches a saturated state after fully soaking and absorbing water, and then it is fully stirred and mixed with the soil in the tree-planting hole to improve the soil Water content: During the planting process, attention should be paid to covering the surface of the tree planting hole with 3cm of crop straw to reduce the degradation of the water-retaining agent by ultraviolet rays in the sun and reduce the evaporation of the soil. The application methods of water retaining agent in drought-resistant afforestation mainly include the following:

　　 dip root method. The main function of applying water-retaining agent when transporting seedlings is to prevent the roots of seedlings from losing water during transportation. The specific dosage is determined by the specifications of the seedlings. When the dosage is small, 1g of water-retaining agent and 400mL of water can be mixed into a slurry, and then mixed with 600g of humus soil and 400mL of water to form a thick mud to dip the roots. For larger seedlings, if the dosage is larger, you can increase the ratio according to the above formula. You can also mix the water-retaining agent with water in a ratio of 1:100 and apply it to the root part of the entire seedling to improve the seedling’s Survival rate. Seedlings are planted in the plant holes, and then soiling, steadiness, watering, etc.; the water-retaining agent can also be evenly sprinkled around the roots of the seedlings, or mixed with ABT rooting powder, and formulated into an aqueous solution according to the ABT instructions, and then follow 1 : 100% mixed with water-retaining agent, add appropriate amount of loess to adjust the mud to dip root; direct application method: the so-called direct application method is mainly in spring afforestation, after mixing the water-retaining agent with the soil, directly put it in the plant hole according to the specific amount. Pay attention that the mixed soil is dry soil, and then plant seedlings, cover the soil, steadily and water, pay attention to the amount of water when watering; seed pill method. The so-called seed pill method is to mix seeds, water-retaining agent, and water in a certain proportion to form a coating liquid, stir it well, and dry in the shade, and then sow. The results of a large number of experimental reports show that the seed pellet method can significantly increase the germination rate and survival rate of sowing and afforestation; the ditching method is mainly applied to the already planted seedlings. When using, first ditch both sides of the seedlings, apply the water-retaining agent in the ditch according to a specific ratio, and then pour water thoroughly. When ditching, pay attention to the depth of the ditch to be beneficial to the plant roots to absorb water. After applying the water retaining agent, water thoroughly.

　　3 Precautions for the application of water retaining agent

　　 The application of water-retaining agent in the process of drought-resistant afforestation needs to pay attention to the following aspects: it must be fully mixed with the soil. When mixing with soil, the ratio of water-retaining agent to soil should be controlled, strictly in accordance with the technical requirements and specifications, and ensure that the water-retaining agent is fully mixed with the soil, because if the mixing is not uniform, the place with too little water-retaining agent in the soil cannot achieve drought resistance The role of water retention is required. On the contrary, if the content of water retention agent in the soil is too much, a paste gel may be produced. In this case, the local soil water storage is too high, which will adversely affect the aeration performance of the soil. In severe cases, it may cause Root system rot is very unfavorable to the normal growth and development of seedlings; during the application process, it should be noted that the water-retaining agent can only absorb water, but cannot produce water. It cannot be used as a water-generating agent, and the water-retaining agent can absorb at most only It lasts for 1 month. Therefore, after applying the water retaining agent in arid areas, if there is no precipitation for a long time, you need to water in time. Irrigate once every one month. Otherwise, the water retention capacity of the water retaining agent will decrease. If you cannot get water for a long time, It will completely lose the water supply capacity; it must be applied in conjunction with other water-saving measures. In the process of drought-resistant afforestation, the application of water-retaining agent is only a water-saving measure, not the only water-saving measure for drought-resistant afforestation. Therefore, it must be applied in conjunction with other water-saving measures to obtain more significant water-saving effects.

　　 Drought-resistant and water-retaining agent can effectively maintain precipitation and irrigation water in the soil, reduce soil water evaporation, and increase soil moisture content. Improving the water supply capacity of the soil to the trees has a certain effect of saving water and drought resistance. Each 667m2 can save 900~1500m3 of water. The water saving effect is more significant, so it has a higher application value in drought-resistant afforestation.