soil Cr土壤铬soiln.土地；土壤；污物，粪便v.弄污soil testing fertilization测土施肥soil resources remediation土地资源修复soil water holding ability土壤持水能力soil vertical distribution土壤垂直分布Soilless - grow seedling无土育苗soil and maize root system土壤-玉米根系系统soil external surface area土壤外表面积soil swelling- shrinkage土壤胀缩soil amelioration material改土物料Soil active organic carbon土壤活性有机碳