margin of cultivation

例句：

1. 1. The researcher found that the marginaleffect of fertilizer on crop yieldwas significant.
   研究者发现，化肥对作物产量的边际效应是显著的。
2. 2. The farmercarefully maintained the soil-land boundary toensure proper drainage and prevent soil erosion.
   农民小心翼翼地维护着土壤与土地的边界，以确保良好的排水和防止土壤侵蚀。
3. 3. The city planners are considering expandingthe urban landscape margin to accommodate more greenspaces.
   城市规划者正在考虑扩大城市景观边际以容纳更多的绿地空间。