what is soil organic materials?

what is soil organic materials? what is soil erosion what is input?(raw materials) 英语翻译The organic carbon content of the soil was relatively hi 请问what materials is it made from?里的from应该加上吗? Who is this?What name?Concrete materials and so on.Please te What are the materials of rigid tube? what are the organic and inorganic definition for oxidation The skyscraper is made ____ new materials. 英语句子语法结构分析The most imprtant soil physical property is soil s always remember to sow your seeds ___the soil is fertile. There is some soil.(water)(改为选择疑问句)