日光温室后坡漫反射幕应用方法及效果验证

日光温室东西垄向栽培可有效提高机械作业效率，但冠层遮挡易造成光照不均，从而影响作物生长发育。针对该问题，该研究提出了适用于日光温室后坡的漫反射幕应用方法，并于试验温室内设置4个东西方向垄，依据理论方法在试验区后坡张挂漫反射幕，以此验证张挂漫反射幕对温室番茄冠层光环境的影响。结果表明：冬季上午，外界光强相对较弱，漫反射幕对冠层光环境的影响较小；中午时，试验区各垄北向来光在冠层1.0和1.4 m高度相比对照组均有显著增强（P<0.05），提升10.4%～68.8%，上方来光光强在冠层1.0 m高度相比对照组显著增强（提升16.3%～30.4%,P<0.05），在1.4 m高度除第三垄外，影响均不显著（P>0.05）；下午，与对照区相比，试验区各垄在冠层1.0和1.4 m高度北向来光光强均有增强，最高提升102.0%；相对对照区，试验区第二、三、四垄上方来光光强显著增强（P<0.05），提升范围为19.7%～54.3%。因此，漫反射幕可将入射到日光温室后坡的光照反射至各栽培垄北侧，从而改善东西向栽培各垄番茄冠层光照环境。

Application and effect verification of diffuse reflective films on the backslope of solar greenhouses

The east-west ridge cultivation technique can effectively improve the mechanical operation efficiency in the solar greenhouses. However, the generally dimmed canopy can be found in the north side of the solar greenhouse and the north side of each ridge, compared with the south side. This study aims to improve the light environment inner tomato canopy, particularly for the better growth and development of the cultivated crops. A theoretical method was proposed to hang the diffused reflective film on the back slope of the solar greenhouse, according to the geographical location and building parameters. The appropriate angle was also determined for the diffused reflective film on the light environment of the greenhouse. The field test was conducted in the solar greenhouse of Hongke Farm (115.97E, 39.62N) in Beijing of China in February of 2022. Four east-west ridges were set in the experimental greenhouse. The greenhouse was separated as an experimental and control section. Among them, a diffuse reflective film with an appropriate angle was hung on the back slope of the solar greenhouse. The tomato plants were managed in the experimental and control sections, according to the normal horticultural practice. The light sensors were placed horizontally upward to measure the light intensity from above at the 1.0 and 1.4 m height of the canopy on the north side of the ridge, respectively. By contrast, the sensors were placed vertically backward to record the light intensity from the north side at 1.0 and 1.4 m height of the canopy. The results showed that the effect of the diffuse reflective film on the canopy light intensity was relatively low in the morning, due to the relatively low light intensity and the greater sun azimuth. At noon, the application of diffuse reflective film was improved the light intensity from the north of each ridge, compared with the control, while the light intensity from the north at 1.0 and 1.4 m increased by 52.4% and 68.8% for the third ridge, respectively. The overall light intensity at the 1.0 m height of the canopy increased for all the ridges. At the height of 1.4 m, only the light intensity of the third ridge at the experimental section was significantly higher than that of the control, and the light intensity increased by 27.1%. In the afternoon, the light intensity from the north of each ridge also increased, and the third ridge increased the greatest, while the light intensity from the north direction increased by 69.2% and 102.0%, respectively, compared with the control. The light intensity of the incoming light from above of the second, the third and the fourth ridge were all significantly increased, and the fourth ridge was resulted in the greatest improvement, indicating both the optimal heights of 1.0, and 1.4 m (46.0% and 54.3%, respectively). Therefore, the diffused reflective film can be expected to increase the light intensity of the inner canopy, providing for the incoming light from the north side. As such, the illumination uniformity of the greenhouse can increase to improve the light environment in the greenhouse.