Preliminary Studies For The South Area Marginal Effect In Sinking Greenhouse

To further optimize the structure of the greenhouse， we chose three different deepsinking greenhouses to observed and contrasted in Pollution-free vegetables planting base ofXingYang Henan province. We tried to analyzing the changes of some environmental factors, suchas soil temperature and air temperature and light intensity and solar radiation in south marginalregion and the middle of the greenhouse and the control of outdoor; and observing the growthvigor of marginal and middle crop; and finding out the boundary point of the south marginal soiltemperature in different deep sinking greenhouses; and identifying the change tendency of the airtemperature, light intensity and solar radiation; and then obtaining the best sinking depth of thesinking greenhouse in Henan province. Thereby, we could provide theoretical basis for structureoptimization of the sinking greenhouse and enriching sunlight greenhouse marginal effect. Theconcrete results were as follows：1. Results of the south soil temperature marginal effect in different deep sinking greenhouse：The marginal points are different in different seasons and different time periods of one day,and it can change with the change of climate, solar radiation, temperature and other factors.Season changes: In January, the farthest distance from the south soil temperature boundarypoint to south base angle in sinking greenhouse of80cm depth was160cm, compared with thesinking greenhouse of40cm depth reduced80cm, and compared with the sinking greenhouse of0cm depth reduced100cm. The nearest distance from the south soil temperature boundary point tosouth base angle in sinking greenhouse of80cm depth was20cm, compared with the sinkinggreenhouse of40cm depth is the same, and compared with the sinking greenhouse of0cm depthreduced20cm.Day changes: In mid-January, one day, the maximum and minimum periods appearedroughly the same of the distance from the south soil temperature boundary point to south baseangle in three different deep sinking greenhouses, they are all≥06：00～09：00and≥15：00～18：00, the time they appeared was uniform with maximum and minimum value of soil temperature.The farthest distance from the south soil temperature boundary point to south base angle insinking greenhouse of80cm depth was180cm, compared with the sinking greenhouse of40cmdepth reduced60cm, and compared with the sinking greenhouse of0cm depth reduced80cm. Thenearest distance from the south soil temperature boundary point to south base angle in sinking greenhouse of80cm depth was60cm, compared with the sinking greenhouse of40cm depthreduced40cm, and compared with the sinking greenhouse of0cm depth reduced60cm.The analysis of the soil temperature from the outside in sinking greenhouse of80cm depth to0～1m from south vertical wall (0～60cm depth) area shows that: the daily change of the soiltemperature of40cm below the surface out of greenhouse0～30cm from south vertical wall isbiggish, and after40cm is stable. The soil exist the point of the low-temperature variable zone andconstant temperature zone. In winter of low temperatures, there is permafrost in outdoor bare soilof Henan province.To sum up, whether it is changes in the winter and spring, changes in one day, the minimumvalue of the south soil temperature marginal effect region all appeared in sinking greenhouse of80cm depth, and the marginal effect can weaken with the increase of the sinking depth ofgreenhouse.2. Results of the south air temperature marginal effect in different deep sinking greenhouse：The overall change trend of indoor air temperature and outdoor the same height airtemperature is basically the same in different sinking depth greenhouse. Morning and evening airtemperature is lower, and indoor air temperature arrive minimum value at08:00pre and post, andhighest values at14:00. In one day, the greenhouse of indoor air temperature is always higher thanthe outdoor. The entirety display of the south marginal air temperature is80cm>40cm>0cm inthree different sinking depth greenhouses.The change of air temperature with the measuring point is relatively complex compared withthe soil temperature because affected by radiation, crop and so on. On the whole, the change trendof the south marginal air temperature with the measuring point is basically the same in threedifferent sinking depth greenhouses. They are all appeared a phenomenon which at first slowlyincreased and then leveled off from the first measuring point to inside of the greenhouse inhorizontal direction.3. Results of the south illumination marginal effect in different deep sinking greenhouse：The daily change of the south marginal illumination is single peak curve in three differentsinking depth greenhouses. Morning and evening maximum is low, following the increasing of thesolar radiation, the illumination maximum value appeared at13:00pre and post．The illuminationof the outdoor control is the largest than three different sinking depth greenhouses. The changetrend of the south marginal illumination with the measuring point is basically the same in threedifferent sinking depth greenhouses, They are all gradually descend following increased of thedistance between measuring point and south base angle. The entirety display of the south marginalillumination is0cm>40cm>80cm in three different sinking depth greenhouses.4. Results of the south solar radiation marginal effect in different deep sinking greenhouse： The daily change of the south marginal solar radiation is single peak curve in three differentsinking depth greenhouses. Morning and evening maximum is low, following the increasing of thesolar radiation, the solar radiation maximum value appeared at13:00pre and post．The solarradiation of the outdoor control is the largest than three different sinking depth greenhouses. Thechange trend of the south marginal solar radiation with the measuring point is basically the samein three different sinking depth greenhouses, They are all gradually descend following increasedof the distance between measuring point and south base angle. The entirety display of the southmarginal solar radiation is0cm>40cm>80cm in three different sinking depth greenhouses.5. Results of the south marginal crop in different deep sinking greenhouse：The measurement on the plant height and stem diameter of the crop showed that: the growthvigor of the three different sinking depth greenhouses was80cm>40cm>0cm. The change trendof the south marginal plants growth vigor with the measuring point is basic ally the same in threedifferent sinking depth greenhouses, they are all gradually better from the south base angle to themiddle of the greenhouse. The growth vigor of the middle plants was obviously better thanmarginal.