炎热气候下基于光谱管理和辐射制冷的温室薄膜材料

Solar spectrum management and radiative cooling film for sustainable greenhouse production in hot climates

炎热气候下,温室内部热量过度累积、气温过高的问题经常发生,严重影响温室内作物的生长发育,大大降低了温室的周年利用率和经济效益.为此,有效调节温室内气温已经成为炎热地区温室栽培需要解决的首要问题.基于光谱管理和辐射制冷原理,本文提出两种不同属性薄膜分别作为温室覆盖材料和地膜,在不牺牲植物光合作用的前提下,减少温室内部热积累,从而延长温室可用生产周期.作为覆盖材料的透明辐射制冷薄膜(T-RC)具有大气窗口波段高发射率,光合有效辐射波段高透过率和近红外辐射波段高反射率,在田间试验中可较PO薄膜温室降温18.6℃,并使樱桃萝卜产量提高62.7%.作为地膜的高反射辐射制冷薄膜(RC)在大气窗口波段具有高发射率,同时在太阳光谱波段保持高反射率.覆盖RC薄膜后,地温可较空白土壤降低12.5℃,并使杭白菜产量增加127.35%.这两种薄膜为炎热气候条件下的温室增产提供了一种被动式、零能耗的新路径.

Global food production needs to be increased by 50%–70%in the coming decades to feed the world[1].However,more frequent weather extremes and global warming trends increase the risk of food crisis[2].Greenhouse cultivation is regarded as one viable solution to this crisis,owing to its crop quality and quantity promotion ability with controlled microclimate.However,heat accumulation inside greenhouses is a serious obstacle for cultivation in the scenario of hot climates.Too heavy heat stress in greenhouse(even as high as 60°C)can cause protein misfolding and harmful metabolites accumulation inside plant cells,shutting the basic physiology of crops[3].Many areas thereby choose to stop planting during hot seasons,which cuts down the annual available time for planting in greenhouse.