Transplanting technique of large seedlings of Picea koraiensis

Xueling spruce is a unique tree species in Tianshan forest sea, evergreen trees with needle-shaped leaves and slightly curved leaves. The fruit ball is long oval, brown, seedlings are shade-tolerant, not resistant to sunburn, frost and drought, usually regenerate well under broad-leaved forest and grow exuberantly under moderate moist conditions and full light. The crown of Snow Ridge spruce is long and narrow, the trunk is stout and straight, and the tree is vigorous and straight.

With the improvement of social economy and people's living standards, people pay more and more attention to urban greening construction. Xueling spruce has become the darling of greening trees because of its beautiful tree shape and evergreen. However, because of its high requirements for altitude, air temperature, humidity and light, for a long time, the survival rate of transplanted Xueling spruce (the Xueling spruce referred to in this paper is a large seedling with a DBH of 8 cm ~ 15 cm and a height of 2 m ~ 5 m) is not satisfactory. The author has been engaged in seedling raising and transplanting management for a long time, and summed up a set of scientific and effective transplanting methods through long-term experiment and exploration. Through practice, the survival rate of transplanting can reach more than 90%.

First, choose transplanting season and weather

The transplanting of Xueling spruce should be carried out during the dormant period. In general, the suitable time for transplanting in the north is spring. The experiment shows that transplanting after the first snow in winter can also achieve a higher survival rate. After transplanting, Xueling spruce grows vigorously and shows excellent landscape effect. It should be noted that spruce transplanting should not choose the zone where the longitude and latitude deviate from the original growing place, otherwise it is not easy to survive. In addition, it is best to choose windless weather when planting, and it is appropriate to transplant before evening.

2. Seedling treatment before transplanting

The spruce to be transplanted was irrigated 3 ~ 4 days before transplanting in spring, and the root system was fully absorbed according to the principle of sufficient irrigation. When transplanting in winter, if the soil ball is loose due to lack of water, it can also be irrigated in advance before the soil freezes. If the soil is frozen without irrigation in advance, water should be poured on the soil ball to promote freezing.

Before transplanting, marks should be made on the south side of the seedling so that the manhole can be planted according to the original position, which can effectively prevent possible summer sunburn (original shady bark) and winter frostbite (original sunny side dry skin) and shorten the adaptation period. Remove disease and insect branches, dead branches and dry skirt branches, and properly trim dense branches and overlapping branches.

3. Preparation of transplanting holes

Dig the planting hole one week before transplanting. The diameter of the planting hole is 40 cm ~ 50 cm wider than that of the transplanted soil ball, and the depth is about 15 cm higher than the height of the soil ball. When digging holes, separate the topsoil from the middle and bottom soil, and clean up the impurities in the soil (ancient gravel, bricks, tiles, grass roots, etc.). When the soil is not good, the soil must be changed. If there are conditions, it is best to use the original soil, and apply about 10 kg of high-quality organic fertilizer at the bottom of the hole. Nutritious soil should be prepared in advance when conditions permit. The specific method is to take 50% of sawdust, 30% of plant ash and 20% of cooked soil according to the weight ratio, fully mix and place for 2 to 3 days, promote its high temperature fermentation, and add appropriate amount of chemical fertilizer as needed. Transplanting in winter can dig holes before the soil is frozen, backfill the empty soil after digging, and dig it again when planting.

Fourth, dig the earth ball and packing

When transplanting spruce, it is necessary to increase the soil ball as much as possible. Planting with soil can ensure the integrity of the root system in the soil ball and keep the big seedlings in close contact with the soil, which is beneficial to the survival and growth after planting. Generally, the round soil ball is excavated according to about 8 times of the DBH of the seedlings, the root system is retained as much as possible, and the diseased root, dead root and longer hairy root are cut and cut. The earth balls are packed with non-woven cloth and nylon rope. The soil ball is excavated when the soil is frozen, and the soil ball does not need to be packaged after digging. If the soil is dry and the permafrost is not deep, it can be irrigated step by step until the complete frozen soil ball is dug out.

V. loading and transportation

When loading the seedlings, make the crown facing the rear of the car, the root close to the cab, and avoid damaging the tree and the root soil ball when loading, transporting and unloading. Long-distance transportation should also pay attention to water spraying, shading, waterproofing, etc., in case of heavy rain should prevent the soil ball from being dispersed.

VI. Colonization

First put the planted soil mixed with fertilizer into the bottom of the pit dug in advance, and then carefully put the soil ball into the pit so that its direction is consistent with the original direction, and the planting depth should be after the sinking of the new soil. the original soil print at the base of the big seedling is flat with the ground or slightly under the ground level of 3 cm ~ 5 cm. If the planting is too shallow, the root system is easy to dry and lose water by the wind and the sun. Planting is too deep, the growth of trees is not prosperous, and even cause root system suffocation, death. The fill should be filled in layers, and the soil ball and the surface should also be covered with nutrient soil. When the backfill is transplanted to 2 / 3 of the height of the soil ball in spring, the backfill is watered for the first time to make the backfill fully absorb water, and then fill the soil after the water has seeped (do not be firm at this time). Finally, a cofferdam is built in the periphery and watered for the second time. After pouring water, pay attention to observe whether the soil around the trunk sinks or crack, if the above phenomenon occurs, it should be filled with soil in time.