Important factors of greenhouse construction

Choose Xiangyang, safe, dry, well drained soil, no infectious diseases place scaffolding.

The basic parameters of

(1) greenhouse construction site selection

To be elected in the leeward Xiangyang, fertile soil, irrigation and drainage, convenient transportation and convenient place to build. The best tap water equipment.

(2) in the area

Considered from the light, temperature, water, fertilizer, gas, seedlings and other factors, the south area of single building type greenhouse area, with 400 square meters is more favorable, "Three North" (northeast, North and northwest regions, with 600). 800 square meters is appropriate. The greenhouse span type is less, the effect is not good, is not conducive to regulate various cultivation environment.

(3) wide thin ceiling

Fork called span. From the cultivation, management and construction, shelter, timber two aspects, as far as possible to ensure that the convenience and durability. Single building type greenhouse, South for the winter season long, short time, high temperature air relative higher Mi she factors, from 6 to 8 meters wide is appropriate, to facilitate the realization of comprehensive adjustment, realize the benign management. The northern region of the single building type greenhouse is 10 ~ L4 wide meters, because the autumn and winter and spring season 3 dogs part warming vegetables to implement the protection of cultivation, and when the edge effect is relatively reduced, there is conducive to the cultivation of various factors of comprehensive adjustment. Among them, steel arch assembled single greenhouse width is l0 meters, a few L2 meters; welded steel bamboo mixed structure of greenhouse and greenhouse, greenhouse, more than 14 meters wide, a few L2 meters, small wind area has reached L5 meters, but more than L5 meters above the height must be increased, or not is firmness, wind resistance, anti snow, is affected by pressure, easy to damage or deformation.

(4) in height

Greenhouse in high and both sides of the shoulder height, directly affects the performance of structure strength, lighting, heat preservation, management and operation. Bamboo and wooden structure, multi column greenhouse, mostly manual ventilation, medium and high L8 meters, the maximum can not exceed 2.2 meters, shoulder height of about 1 meters. In the design and construction of reinforced plastic welding and steel tube greenhouse, the curvature problem should be taken into account, and the curvature of O.15-0.2 is required to have better wind resistance, snow and daylighting. The curvature for the high span ratio, i.e. curvature (= top a shoulder height, span). For example, the span is L2 meters, the top height is 3 meters, and the shoulder height is l.2 meters. Then the curvature is 0.15, so the height of the two types of non pillar greenhouse is more than 2 meters. Beijing region for more than 2.6 to 3.2 meters, the maximum can not exceed 3.5 meters. Although with the increase of height can make the temperature change trend is stable, but also conducive to the field work and the growth of crops, but in early spring slow heating and hot air in the upper layer, is not conducive to the cultivation.

(5) in length

Mechanization in China is low, fertilizing, planting, product handling is completed so as far as possible to avoid the human, shed is too long, in order to reduce the burden of human, 40 to 60 meters long is more appropriate, if there is a small machinery for farming, as an available greenhouse span of L5 meters, length of 90 m circle Sr and thin-wall galvanized pipe, more conducive to give full play to the role of mechanical operation and greenhouse production potential.

(6) the distance between the shed

Concentrated construction of greenhouses, and single building structure, maintain 2 meters distance to shed two, before and after the two row to maintain the distance of 4 meters, to facilitate ventilation, and drainage ditches, and prevent the front of the rear shade in winter.

(7), the wind resistant design of greenhouse chezlee

Lost shed snow load capacity is affected by many factors, such as small shed body curvature, the snow is not easy to fall naturally, will inevitably increase the load, even the roof pressure lying. Assume that a plot setter 30 cm thick, the snow load is required to reach 20 to 22.5 kg / m2; a wind of 8, speed can reach 17.3 - 20.7 M / s, wind load is to be able to withstand 18.3.26.9 M / s, in order to ensure the safety of the shed body.

(8) in the direction of

Refers to the single building type greenhouse to extend or extend to the north and South East, mainly from the light intensity into account. In the cold (latitude 350, I) winter, things extend longer than the northern and southern lights, the average intensity increased by about l0%, but due to the limited thermal insulation of the greenhouse, winter can not be cultivated. It can only be produced in the 3 seasons of autumn, spring and summer, and the light conditions can basically meet the requirements, resulting in no significant difference in yield, and the vertical arrangement of the customary cultivation beds and the long canopy is convenient for operation. Therefore, most of the direction of the greenhouse for the southern jE to extend, but also to east-west extension, North and South Ridge Cultivation, the effect is slightly better.

(9) greenhouse ventilation

Is mainly to adjust the gate in adjusting the temperature, humidity and gas composition. The width of the canopy is over l0 meters, and more than 3 vents are used, that is, the remaining raphe and the two side seam. The raphe was highest in the central part of the greenhouse. The seam is on the shoulders of both sides of the canopy,.L to 1.2 meters above the ground. The air vents let in the cold air from the side seam, and the hot air is discharged from the top seam. The ventilation effect is good. When no ventilation is necessary, the two films are closed, and the overlap of the two films is more than 10 centimeters. Span 10 meters below the shed, mostly assembled style, the top has taken over, the shape of the partial convex shape, generally do not leave the top seam, using two side seam ventilation, if the top seam, then the seam opening and closing more difficult.