冬小麦冠层截留及其消散过程

Canopy interception and its dissipation of winter wheat

采用擦拭法测定冬小麦不同生育时期的冠层截留。研究发现冬小麦最大冠层截留量为1mm,发生在抽穗开花期,也是叶面积指数最大值时期。在冬小麦生长前期,冠层截留随着叶面积指数的增大而增大,后期冠层截留随着叶面积指数的减少而减少。冠层截留消散过程主要受空气温度和湿度等气象要素的影响,温度越高、相对湿度越低,冠层截留消散的越快;温度越低、相对湿度越高,冠层截留消散的越慢。冠层截留消散过程还受小麦水量的影响,在喷灌刚结束时,小麦植株上的水分多,冠层截留消散的较快,随着水分的蒸发,冠层截留消散的速度减慢。

A wiping method was adopted to measure canopy interceptions in different growth period of winter wheat. The results showed that the minimum canopy interception of winter wheat was 1mm and appeared the period from heading to flowering, i.e., the period with maximum LAI. The canopy interception rose with increased LAI in early growth of winter wheat and declined with decreased LAI in late growth of winter wheat. The dissipation of the canopy interception was affected by atmospheric temperature and humidity; the higher the temperature was and the lower the humidity was, the quicker the dissipation of the canopy was; contrarily, the lower the temperature was and the higher the humidity was, the slower the dissipation of the canopy interception was. The dissipation of the canopy interception was also affected by water on wheat plant; at the end of sprinkle irrigation, there was much water on wheat plants and thus the canopy inception more quickly dissipated; as the water on wheat plants decreased because of water evaporation, the canopy interception dissipated at a reduced speed.