Effects of Microtopography in Urban Relocation Green Spaces on Surface Runoff Regulation and Plant Growth: A Case Study of Shanghai Expo Cultural Park

This study aims to reveal how microtopography (slope gradient, position, and aspect) in newly established urban green spaces regulates soil nutrients and plant growth by influencing surface runoff. Focusing on Cinnamomum camphora and Ginkgo biloba in Shanghai Expo Cultural Park, we found that:As slope gradient increases, surface runoff intensifies, leading to soil nutrient loss. Consequently, plants on upper slopes suffer from nutrient deficiency and limited growth, whereas plants on lower slopes benefit from the accumulation of water and nutrients, showing enhanced growth. Slope aspect also modulates plant growth by affecting light and soil conditions.In conclusion, plant growth is significantly negatively correlated with surface runoff and positively correlated with soil nutrient status, with slope gradient being the most influential microtopographic factor. These findings offer scientific guidance for the microtopographic design, tree species selection, and landscape construction of future urban green spaces.