| The air temperature and light condition and its effects on crop planting system in solar greenhouses are studied. The results show that: because the light time is less than 12 h during the production period with plastic film, covering solar greenhouses in northpart of China, on condition that light are not increased or replenished manually, are not suitable to grow long-day crops that produce fruits as main production, but are suitable to grow long-day crops that supply nutritorium as main production, short-day crops and intermedium crops that are not sensitive to light time; the notable increasing of annual active accumulated temperature (≥10℃) , provides necessary condition for multiple cropping in solar greenhouses; the distributing differences of light intensity and air temperature in the directions of north - south and uprightness supply favorable condition for intercropping, relay cropping and multistory cropping in solar greenhouses. Therefore, it is possible to realize poly-dimension utilization of space-time resources within solar greenhouses by adopting rational crop planting system. |