1.They used it to fertilize soil, and the resear3chers have found that this soil is still some of the richest and most fertile in the world.
他们利用这些炭来给土地施肥，研究者们发现那些土地到现在还仍然是世界上最肥沃最高产的土地一部分。
2.Material, especially barnyard or stable dung, often with discarded animal bedding, used to fertilize soil.
肥料用于使土壤肥沃的材料，尤指谷场或马厩中的肥类，常含有废弃的动物垫草窝
3.Nitrates fertilize soil.
硝酸盐使土地肥沃。
4.Manure: To fertilize (soil) by applying material such as barnyard dung.
施肥：用肥料如谷场旁的粪肥来肥沃（土壤）