downward enrichment

例句：

1. 1. The research on downslope flow is crucial for understanding the dynamics of mountainous terrains.
   对坡面流的研究对于理解山地地形的动态至关重要。
2. 2.Downward enrichment has been shown to increase crop yields in arid regions.
   研究表明，向下富集可以提高干旱地区的作物产量。
3. 3.The concept of downward enrichment has been applied in various fields such as environmental science and engineering.
   向下富集的概念已被应用于环境科学和工程等多个领域。