The latest course of cultivation techniques and methods of Yellow Poplar

Populus tomentosa is not strict on soil, sandy soil, loam, brown soil can be planted, but it is best to contain organic rich loam land. The land type is required to be flat when preparing the land. Combined with deep ploughing, add organic fertilizer, about 2000 kilograms per mu. When applying base fertilizer, we should pay attention to the full maturity of organic fertilizer and apply it deeply in the planting hole. Under the climatic conditions in Beijing, spring is the main time to plant seedlings, which is usually two or three days before the Qingming Festival in early April. The general row spacing of Populus tomentosa planted in the open field is 0. 5 × 1.5 or 0. 4 × 1.2 meters, planting about 1000 to 1500 plants per mu.

With the increase of the age of the tree, the seedlings can be raised from another plant in the future. Populus tomentosa seedlings can be planted in holes or furrows. Before planting seedlings, according to the planned row spacing, dig holes or trench according to the planting spacing, the ditch depth should be greater than the seedling root depth, about 40 cm deep. Before planting, the base fertilizer should be applied deeply, and the fully mature organic fertilizer should be mixed with the soil and applied to the bottom of the hole. When planting, remove the nutrition bowl of the seedlings and arrange them in the ditch according to the distance between the plants, so that the roots come into contact with the soil and step on the soil. Step on the earth ball in real time after covering the soil, do not crush the earth ball, but should step on the gap between the soil ball and the tree hole. The depth of soil cover is slightly deeper than the original soil imprint, so as to prevent the soil from sinking and exposing its roots after irrigation, thus affecting its survival.

Watering

Watering is the main measure to ensure the survival of seedlings, especially the northern spring drought and less rain, large evaporation, if insufficient water supply, it will seriously affect the survival rate of seedlings. After planting seedlings, ridges can be made with soil every 4 to 6 rows to facilitate irrigation. It is required to irrigate the first time within 24 hours after planting seedlings, the second time every 3 to 5 days, and the third time every 5 to 7 days. After three times of irrigation, you can decide whether to irrigate or not according to the weather and the condition of seedlings.

The amount of water should not be too large or too small, the amount of water is too large, the soil becomes soft, and the seedlings are easy to lodge; the amount of water is too small, affecting survival. Planting seedlings after irrigation or more rainfall, seedlings are easy to lodge, tilt or root, if this phenomenon occurs, should immediately straighten, cultivate the soil, step on, otherwise because the seedlings are sprouting and growing, the stem of the seedlings will bend within a few days. When supporting seedlings, you can first dig up the soil near the roots of the seedlings, straighten the seedlings, find the direction between straight rows and plants, and then return the soil to earth. After three consecutive irrigations, when the soil of the seedling bed sinks and potholes appear, it should be leveled and filled in time. It can also be combined with ploughing to flatten the ground so that the seedlings receive the same amount of water and prevent the imbalance between drought and waterlogging. Yellow poplar trees prefer water, so they should grasp the principle of "better wet than dry" in watering.

In the seedling stage, the root system is shallow and sensitive to water, generally in order to keep the surface soil moist, should be irrigated for a small number of times. In the period of rapid growth of seedlings, rapid growth and large water demand should be irrigated with flood water to make it wet and dry. However, in the later stage of growth, in order to prevent seedlings from growing and promote Lignification, irrigation should be stopped. Generally speaking, watering should be controlled at the end of summer. Irrigation time: each watering time, preferably in the morning and evening, not in the highest temperature at noon.

Intermediate ploughing and weeding

Weeding in mid-tillage is a regular work in seedling management. Ploughing and weeding are two concepts, but they can be combined.

In general, weeding is best carried out after rain or irrigation. When the soil is moist, the grass is pulled up by the roots, and the effect of loosening the soil is good. Soon after the seedlings are newly planted, most of the soil surface is exposed to the air, which is not only easy to dry, but also easy to grow weeds. During this period, intertillage and weeding should be carried out in time to promote the root development of seedlings.

In general, the roots of the seedlings should be slightly shallow ploughing, and the rows between the plants can be properly deepened, usually 3 to 5 cm. Ploughing in the rainy season can promote gas exchange and evaporation of gaseous water, which can prevent seedling waterlogging. In the northern region, it is generally dry in spring, and the growth of weeds has stopped in autumn, which should be dominated by mid-ploughing and weeding in summer. The rapid growth period of weeds is before and after the rainy season, during this period, weeding should be strengthened, and weeding should adhere to the principles of early weeding, small weeding and weeding. All the underground parts of perennial weeds must be dug out, otherwise, it will be more and more difficult to remove.

Topdressing

Topdressing can timely supplement the large amount of nutrients needed by seedlings in the period of vigorous growth and development, promote the growth and development of seedlings and improve their quality. Yellow poplar needs more phosphorus in the seedling stage, more nitrogen in the peak growing season, and more potassium in the autumn growth period.

After the seedlings are planted, 0. 5% can be sprayed on the leaves. 4% potassium dihydrogen phosphate solution should be carried out on cloudy days or when the air is moist in the morning or evening. Generally, you can spray three or four times of potassium dihydrogen phosphate on leaves every month. The newly transplanted yellow poplar seedlings should be fertilized in the early stage, but we should pay attention to the fertilizer concentration should not be too high, so as not to burn the new roots. In the fast-growing period of seedlings, the amount of fertilizer should be increased and the times of fertilization should be increased at least once a month. Urea is available for topdressing nitrogen fertilizer, which can be divided into two methods: dry application and wet application.

Dry application can be spread and ditch application, spreading is to spread chemical fertilizer evenly on the inter-seedling soil, and then shallow hoe to cover the soil twice; ditch application is to open a ditch between the rows of seedlings, generally 15~20cm away from the seedling root, apply chemical fertilizer into the ditch, and then cover the soil. During ditch application, it should be noted that the ditch depth should be in the distribution layer of the root system, so as to facilitate the absorption of fertilizer by seedlings. Wet application is to dissolve the fertilizer in water and sprinkle it comprehensively on the seedling bed or between the rows. It is best to irrigate again after application to avoid burns. The application of nitrogen fertilizer should be carried out in spring and summer, and the last application of nitrogen fertilizer should not be later than the Beginning of Autumn. In order to prevent the seedlings from overgrowing and reduce the overwintering ability of Populus tomentosa seedlings. From August to September, the application of nitrogen fertilizer must be stopped, and the main fertilizer should be phosphorus and potassium fertilizer. Promote the Lignification and root growth of Populus tomentosa seedlings, and improve the cold resistance of seedlings.