01036nam a2200205Ia 4500 CTU_138585 210402s9999 xx 000 0 und d 631.417 K96 Kumada, Kyoichi Chemistry of soil organic matter Kyoichi Kumada Tokyo Japan Scientific Societies Press 1987 In this book, humic acids are classified into A, B, Rp and P types, based on their optical properties. The elementary composition and other chemical properties of humic acid types are shown to be regularly different from each other. A new method for humus composition analysis applied to various kinds of soils in Japan and several other countries indicates that the diversity of humus compositions of soils is systematically understandable. Humus,Soils,Đất,Đất mùn Humic acid content,Phân hủy mùn cưa Trọng Hiếu Trung tâm Học liệu Trường Đại học Cần Thơ