The results also indicated that the color of the fourth LFT was mainly affected by NSDB among the top 4 leaves and was lighter than the third LFT when nitrogen supply was insufficient for the need.

• 研究证实顶 4叶叶色受氮素供需差的影响最大 ,当土壤供氮不能满足库需氮时 ,顶 4叶叶色浅于顶 3叶