Effects of Long-term Located Fertilization on Contents of Soil Humus

The effects of long term located fertilization on content of soil humus in fluvo aquic soil, arid red soil and paddy red soil were studied. The results showed that the content of organic matter, humus, and active humus increased and the level of humic acid and fulvic acid increased correspondingly in the topsoil of fluvo aquic soil, arid red soil and paddy red soil, with long term application of inorganic fertilizer (NPK), organic manure and combined application of both, with the latter being the most .In addition , application of organic manure and combined application of inorganic fertilizer and organic manure could increase the ratio of humic acid to fulvic acid. The effect of long term located fertilization on organic matter was included not only the topsoil (0~20cm), but also the depth of 20~100cm, and most significant in the depth of 0~60cm, and in fluvo aquic soil.