Seedling management of Fraxinus mandshurica
1, irrigation and drainage. During the germination of ash seeds, the bed surface should be kept moist and watered several times. After the seedlings come out, the cotyledons are fully unfolded and enter the vigorous growth period. Irrigation quantity should be more, and times should be less. Irrigation should be done every 2 ~ 3 days 1 time, and thoroughly every time. Irrigation time should be carried out in the morning and evening. It rains in autumn and needs to be drained in time.
2, pruning. Fraxinus mandshurica is a false dichotomous tree species. In order to cultivate Gao Qian, the basic principle is to change the top into a joint branch mode, so that the trunk can grow upward and form a Gao Qian. The plastic methods are natural pistachio shape, sparse trunk shape and multi-head trunk shape. Because of its weak drought, no obvious stratification and strong ability of germination and tillering. Trimming resistance. Its opposite buds tend to extend upward at the same time If the force is uniform, it is easy to form a binary tree shape, which affects the high growth. In order to form a single trunk tree, when the new branches grow to 10c m after germination, it is necessary to select robust new branches for trunk culture.
The other weak branch was hollowed out to inhibit its growth and used as an auxiliary branch. For the new branches appearing in the lower part, a part should be reserved as auxiliary branches, and the new branches near the base or below 1m should be drained at the base. In the winter of the following year, the seedlings were cut, and the height was about 2m, which was relatively strong. At this time, the auxiliary branches left last year can be thinned to the base, and then the apex of the central main branch can be cut off by about 1/3. The opposite buds under the incision should be peeled off, and the direction of remaining buds should be relative to the direction of the previous year, so as to grow continuously from left to right and facilitate the formation of straight stems. 3. Top dressing. Fertilization of ash trees should be based on base fertilizer. In order to make seedlings grow fast and strong, chemical fertilizers should be applied to supplement them at the peak of growth. Nitrogen fertilizer should be applied to Fraxinus mandshurica seedlings, and more nitrogen fertilizer, potassium fertilizer or several fertilizers should be applied in the fast-growing period. In the late growth stage, nitrogen fertilizer should be stopped, potassium fertilizer should be applied more, and quick-acting fertilizer should be the main topdressing, with a small amount for many times.
4, thinning seedlings. In ord to adjust that density of ash trees,
Seedlings need to be replanted by thinning. In the nursery of Fraxinus mandshurica seeds, the seedlings are generally interplanted twice, the first time is when the seedlings grow two pairs of true leaves, and the second time is when the leaves overlap each other. Intercropping should be carried out when the soil is wet after rain. Prevention and control of common diseases and insect pests of ash tree
Brown spot disease: This pathogen harms ash leaves and causes early defoliation.
Affect the annual growth of ash trees. Pathogen attached to the front of the leaf, scattered with polygonal or nearly round brown spots, the center of the spots was grayish brown, the diameter was 1-2 mm, and the serious disease spots were 5-8 mm. The front of the spots were covered with brown mildew spots, which were the fruiting bodies of the pathogen. Prevention and control methods:
1. Sowing seedlings should be interplanted in time, and fertilizer and water management should be strengthened in the early stage to enhance the disease resistance of Fraxinus mandshurica.
2. Clean the diseased leaves on the ground of the seedlings in bed in autumn to reduce the source of overwintering bacteria.
Spraying 1: 2: 200 times bordeaux mixture or 600 times 65% zineb wettable powder for 2-3 times from March to July has good disease prevention effect.
Prevention and control of fingernail claw;
1, adult occurrence period, mobilize the masses to kill sooner or later.
2. Cut off the spawning branches and larvae.
3. Before the larvae mature into the soil, put the chickens and ducks in the woodland for beak feeding.
4. When adults occur, spray 90% trichlorfon or 80% dimethoate 1000 times each.
5. During the larval damage period, spray 25% diflubenzuron No.3 1000 times or 25% Muyajing WP 1500-2000 times.
In pest control of Fraxinus mandshurica seedlings, we should start with winter ploughing, soil disinfection, careful selection, seed disinfection, rational fertilization, timely early sowing and management to prevent the occurrence of pests and diseases. If pests and diseases are found, they must be eliminated as soon as possible to ensure the healthy growth of ash trees.