Abstract: Based on the data of air temperature and humidity obtained from inside and outside of plastic greenhouse as well as of wind on the opening of the greenhouse, some properties were found of the time and space distribution of air temperature and humidity, especially, the inequality of the temperature-preserving and humidity-preserving effects in the closed greenhouse except a certain time before noon when both effects are equal. In addition, a general relationship was discovered between the quantity of ventilation on the opening of the greenhouse and the temperature and humidity differences between inside and outside of the greenhouse.

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