Cultivation method of elm

1, select 20 ~ 40-year-old robust mother trees, and immediately collect seeds when samara turns from green to brown in mid-April. Because it will fly around in a few days after maturity, it is impossible to collect it. One thousand seeds of Elaeagnus mollis weigh about 5 ~ 6 grams, with 654.38 0.8 thousand seeds per kilogram, and the seeds are shriveled. Because the seeds are collected and sown, the germination rate will be lost after one month in the seed bag.

2. Seedling Ulmus pumila can be cultivated by sowing or cutting.

Sowing and seedling raising: choose a nursery with convenient irrigation and drainage, sandy loam and yellow soil, evenly sprinkle 300 kg of vegetable cakes per mu, and build a border after ploughing and harrowing. After harvesting the seeds in mid-April, the seeds can be sown except the shriveled grains. Sowing with wings, the row spacing is 25 cm, and the sowing amount per mu is 2 ~ 2.5 kg. It is covered with burnt marl, so thick that you can't see the seeds, and it is also covered with Leymus chinensis. It germinates about 7 ~ 10 days after sowing. After the seeds germinate and are unearthed, uncover the grass covered by the seedbed, weed and topdressing in time. If carefully managed, 1 year-old seedlings can leave the nursery, the height of seedlings is about 1 m, and the root diameter is 1. 1 cm. The yield of seedlings per mu is about 1.5 ~ 20000 plants.

Cutting seedling: hardwood cutting is adopted. Before the buds germinate from early February to early March, the 1 ~ 2-year-old branches of young trees or sprouting trees are cut with a thickness of 0.3 ~ 1 cm, and the cuttings are cut into 10 ~ 15 cm and inserted into one-half or two-thirds of the soil. About 40 ~ 50 days after transplanting, the roots germinate, and several buds grow to about 10 cm, and the lateral buds are removed. The annual cutting seedlings are about 1 m high and the roots are 2 cm thick. 1. Selection of afforestation site: to build fast-growing timber forest, the afforestation site should be selected at the lower part of sunny slope below 1000 meters above sea level, or in deep, fertile and humid mountainous areas on both sides of the valley.

2. Soil preparation method: split the mountain in late autumn and early winter, remove weeds and prepare soil in blocks. Dig a permanent planting pit 60 cm in diameter and 50 cm in depth.

3. Planting density: the planting density is 2.5× 3.0m (88 plants per mu) or 2.0× 2.0m ..

4. Afforestation method: bare-rooted seedling afforestation in early spring. After emergence, the roots should be dipped in mud to prevent excessive water loss. When planting, the topsoil should be filled around the roots of the seedlings and in the planting holes to ensure that the seedlings are upright, the roots are comfortable and the mud is compact. The survival rate is generally above 95%. After afforestation, young forest tending management should be strengthened in the first three years. Weed and loosen the soil 1 ~ 2 times a year, expand the hole and bury the green. In the winter of the third year after afforestation, appropriate pruning will be started to promote the growth of tree height. Thinning in stages after canopy closure.

The thinning period is about 20 years and the main cutting age is 35 ~ 45 years. From April to May, the adults of scarab are unearthed, and they like to eat tender leaves and buds, leaving only veins after eating leaves. Most of them occur in warm and windless weather, which affects growth. It can be killed by shaking trees in the evening at the peak of adult emergence, or poisoned with 50% dichlorvos emulsion 800 ~ 1000 times.