题目内容

园艺设施在寒冷季节透光率只有自然光的50~70%，透明覆盖材料用时间长而染尘、老化等因素，使透光率甚至降的更低。()

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聚乙烯透过太阳辐射能力优于聚氯乙烯，但，聚乙烯保温性能较差，棚内日温差大。()

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