My father also plants "Isote", which we call the Yucca plant in the US, close togehter in rows in areas with a potential for soil erosion or in those areas already showing signs of erosion. The growing plants serve as a living barrier, capturing any eroding soil, thereby keeping the soil on the land and out of the streams.  We also cook the white flowers in soups. They're delicious!

 

Finally, my father leaves large trunks from fallen hardwood and shade trees, as well as banana trunks (once an individual trunk produces  bananas it yields no more and is cut down with a machete) which provide physical barriers to water/soil flow.  These are just some of the soil conserving practices used by my family for generations, keeping our land healthy and productive and the watersheds clean!