The Comparative About Microclimate And Late Autumn Cultivation Effect Between Multispan Greenhouse Covered With Single And Double Sheds In Central Region Of Jiangsu Province

With the development of the material structure technology, the economy level and social needs, various protection facilities are playing important roles in advancing our national agricultural production and technological progress on their strengths. As one kind of Horticulture facility, Multi-span greenhouse achieved good development these years. While continuing to expand the application acreage of Multi-span greenhouse, rarely heard domestic reports about performance of each factor as important measures in its internal environment and the research of cultivation results in practical application. This paper, based on the central region of Jiangsu Province, take GLP-8432 type double-span greenhouses and GLP-8432 type single-span greenhouse as object of study. Comparative study of the difference of air temperature, soil temperature, air humidity, and late autumn cucumber cultivation effect between the two type of covers. Try to analyze the experimental results for the selection of the type of coverage and guide the actual production operation. Through comparative studies, we get the following points of results:1. The differences and discipline of air and soil temperature between single shed and double sheds:Early spring air-temperatures comparison results shows, single shed average-minimum temperature 2.3℃ higher than the open field, double sheds average-minimum temperature 4.2℃ higher than the open field. Sunny, cloudy, cloudy, rainy day’s minimum temperature in single shed were 2.7℃、2℃、2.2℃、1.6℃ higher than the open field in proper order. Sunny, cloudy, cloudy, rainy day’s minimum temperature in double sheds were 3.9℃、4.1 ℃、4.6℃、3.2℃ higher than the open field in proper order. The effect of maintain the air-temperature in double sheds was better than single shed. The average increase for each additional layer covering about 2 ℃. The daily temperature variation amplitude of sunny and cloudy days were bigger than rainy day and overcast sky day. Sunny and cloudy days always have a high temperature at noon, so before the temperature becoming higher, we should open the vents to lower the temperature.Early spring soil-temperatures comparison results shows, the average minimum temperature of soil surface in single shed was 2.1℃ higher than the open field, and the data of double sheds was 3.4℃ higher than the open field. Double sheds had more superiority in maintaining the soil-temperature in than single shed. The change magnitude of soil-temperature was smaller than the temperature. Daily changes of temperature in deep soil was smaller than surface of soil. And deep soil-temperature go down later than surface. Both deep soil-temperature and surface soil-temperature in all kinds of weather show that the effect of maintain the soil-temperature in double sheds was better than single shed.Early autumn air-temperatures comparison results shows, double sheds appear easier to happen heat stress above 35℃ than single shed. The cooling capacity of double sheds was weaker than single shed. Heat stress occurred mainly in the sunny and cloudy days, The average maximum-temperature of double sheds was 2.3℃ higher than single shed. The heat stress in the two types of sheds was both more serious than the open field.2. The differences and discipline of relative air humidity between single shed and double sheds:The degree of high humidity in double shed was more serious than the degree in single during early spring. Double shed was more prone to occur water logging. The high humidity in the double and single shed both had eased when the weather was sunny or cloudy. When the weather is rainy or overcast sky, the high humidity would continue throughout the day. So after a rainy or overcast sky day, we should enhanced ventilation and scattered wet on time.The humidity in double shed was also higher than single shed during early autumn, but the difference was not obvious. The magnitude of changes in humidity was very wide when there is bright sun on the sky. it means that extremely low humidity would happen during the daily time. So we should do more irrigation to ensure the plants have enough water. The same as early spring, after a rainy or overcast sky day, we should enhanced ventilation and scattered wet on time.3. Differences of late autumn cucumber cultivation effect between single shed and double sheds:The plant in double shed obviously thinner and weaker than single shed during the mid-late plant growth time. Leaf width in single shed was 7.4% bigger than it in double shed during growth medium and 12.2% bigger than double shed during last period of growth. Stem diameter in single shed was 7.7% bigger than double shed during growth medium and 5% bigger than double shed during last period of growth. The leaf width and stem diameter had no significant difference between double and single shed during prophase of growth. Compared with the open field, the two cover treatment seemed obviously thinner and weaker. Robust level of plant in double shed can not compare with that in single shed. It was more difficult for the plant protection, cultivation and management in double shed than single type. So, we need more effective Management measures to ensure the healthy growth of plants.The yield in double shed was 5% less than single shed during prophase of growth. During the mid-late plant growth, there was no significant difference in yield. The average number of fruit per plant during the growth period was all 5, only in the open field. The all production in double was less than single. Double shed has no advantage over me. But the harvest time of double was 5-6 d later than the single shed, and has more advantage than single shed in late-effective. Want to know the specific benefits, we need further research.