Their horizontal variation, in the morning, was that the east side was high while the west side was low, in the afternoon the results were opposite.

• 1 单、双层塑料大棚光照强度的季节变化由冬到春呈现由低到高的上升趋势，单层塑料大棚的光照强度明显大于双层塑料大棚。