Shelterbelt Construction of Walnut Orchard

   shelterbelt can improve the ecological environment of walnut orchard, prevent and reduce the harm and invasion of wind, sand, cold and early, reduce wind speed, reduce soil moisture evaporation and soil erosion, adjust temperature, weaken cold current, increase soil water content, and ensure normal tree growth and fruit.

   1. The function of shelterbelt

According to the measurement of temperature and humidity of    (1) regulating area, within the protection range of shelterbelt, the summer air temperature can be reduced by 0.7-2.0 ℃, the relative humidity can be increased by 3.5%-14%, the soil water content can be increased by about 9%, the temperature difference between day and night can be reduced, and the frost-free period can be extended by 3-5 days, which significantly improves the ecological environment of the park and lays a good foundation for high yield and high quality.

   (2) reducing wind speed and wind damage is beneficial to the growth and development of fruit trees and wind pollination, and strong wind has a destructive effect on fruit trees. In the case of strong wind during the flowering period of walnut, it is easy to cause damage to flowers, fruits and other organs, affect pollination and fertilization, and reduce the rate of fruit setting. The strong wind accelerated leaf transpiration, aggravated tree water loss and soil drought. In addition, strong winds also cause soil erosion, blow away topsoil and aggravate soil barren. Through the construction of artificial shelterbelt, the wind speed can be effectively reduced and the wind damage can be reduced.

   2. Types of windbreaks

According to the windbreak characteristics,    usually divides the shelterbelt into the following two types.

   (1) tight type, that is, airtight shelterbelt, is a multi-row shelterbelt planted with large, medium and small canopy trees and shrubs with compact branches and leaves, which has a close structure from top to bottom, forming a tall and compact tree wall. The windbreak range of this kind of forest belt is small, but the protective effect is good.

   (2) this kind of protective forest is composed of a layer of large trees and a layer of shrubs, and is composed of loose trees and shrubs. The forest belt has a ventilated mesh structure, and when the strong wind passes through the sieve, it slows down the wind speed and plays a protective role. But the effect of windbreak is worse than that of tight shelterbelt.

   3. Configuration of shelterbelt and selection of tree species

   (1) the configuration of the shelterbelt usually sets up the main shelterbelt and secondary shelterbelt to form a shelterbelt network, with 4-8 rows of trees in the main shelterbelt and 2-3 rows of trees in the secondary shelterbelt, with trees in the middle of the shelterbelt, shrubs on both sides, and mixed planting of trees and shrubs. The row spacing of tight shelterbelt is 0. 5%. 5 ~ 0.7 m X 1. 5 meters, the row spacing of ventilated shelterbelts is 1: 1. 5 meters X 2.5 meters, and the row spacing of shrubs is 1 meters X 1 meters.

When configuring the    windbreak belt, you should pay attention to:

The   ① main forest belt should be perpendicular to the local main wind direction, and the semi-ventilated forest belt should be adopted.

The   ② secondary forest belt is perpendicular to the main forest belt, and the auxiliary main forest belt blocks harmful winds in other directions.

The distance between the two main forest belts of   ③ should be 200 ~ 400m, and the secondary forest belt can be increased to 50000m. The distance, width and height of the forest belts in different areas should depend on the local maximum wind speed. The shelterbelt in the south of the orchard is 2030 meters away from the fruit trees and 1520 meters in the north. Roads and canals can be set up.

When the   ④ forest belt passes through the local highest point, it can be established along the watershed, and when passing through the valley mouth, it should leave a gap at the partial valley mouth, so as not to intercept the cold air across the valley and intercept the cold air in the valley, which is conducive to the discharge of cold air and reduce freezing damage.

   (2) the tree species of shelterbelt should have strong adaptability, fast growth, upright crown and certain economic value. in addition, the most important point is that they can not share the same diseases and insect pests with walnut. The tree species commonly used as protective forest in northern China are: Poplar, elm, early willow, Toona sinensis, ash, Platycladus orientalis, black pine, mountain stator, Hawthorn, du pear, soap horn, walnut, maple and so on; shrubs are diameter willow, pepper, thorn, acacia, sour jujube, thorn rose, Muquan and so on.