Effect on Combined Forms of Soil Humus in Black Soil Under the Soil Removal on Long-term Fertilization Located Experiment

In order to ascertain the change of soil humus when the changes of environment and soil mass,the change of the contents of humus in black soil under the soil removal were studied on the basis of the soil removal of long-term located experiment field.The results showed that the content of soil organic carbon and organic carbon in heavy fraction had significantly positive correlation,and had the same trend before and after the soil removal,the trend of treatments was MNPKMNPKCK.The soil complex amount of treatments was MNPKNPKMCK,soil complex degree was just the opposite trend.The soil complex amount and soil complex disagree was lower after soil removal.The form of soil humus mainly took on the decreasing of loosely combined humus and the increasing of tightly combined humus.The treatment of MNPK had the smallest variation of 0.2%~2.5%,M treatment had smaller variation of 4.5% ~6.0%,the CK treatment of 10.5% ~20.0%.It showed that long term rational fertilization,especially organic and inorganic fertilizer could not only activate the soil humus,at the same time,increase the buffer capacity of itself when environment change.