Discusses the application range, the technical characteris tics of small-sized air-source heat pump cooling(heating) unit,t he thermodynamic calculations of the unit cooling (heating) circle,the unit test installations,the test instruments,and the test results.

The results show that the evaporation in 0～30 cm soil layer of cold wheat field is lower than the that of the warm wheat field from turning green stage to maturing stage;The amount of water consumed by the soil a of the cold wheat field a day is 31.

Studies of phosphorus uptake and accumulation of cold type wheat;

Fertilization effects of yield and its components of cold type wheat;

Studies on nitrogen uptake and accumulation of cold type wheat;