The Changes In Surface Properties And Its Relationship With Soil Acidification Of Long-term Fertilization Clay Complex

By taking the long-term located fertilization soil as the research object, determinated clay complex surface charge was accorded to Mehlich method, and analyzed the changes in surface properties and its relationship with soil acidification of long-term fertilization clay complex, the results were as follows:It reduced the specific surface of clay complex by long-term single application of chemical fertilizer, NK fertilizers for a long time made the decreased degree of specific surface to be the most, and the single fertilization or combined application of nitrogen fertilizer also greatly reduced the specific surface; The specific surface of clay complex of matched group CK was the biggest, it was accordance with the rule of organic matter. The specific surface in group C of long-term fertilization was less than group CM₁ and CM₂ With organic fertilizer, but there was no significant difference between group CM₁ and CM₂. The outer surface of clay complex was greater than the inner surface in the long-term fertilization soil. Long-term single application of chemical fertilizer could reduce the contents of CEC_8.2, CEC_P, CEC_V, CEC_V/CEC_8.2, CECm, net negative change and surface change density of the clay complex, especially single fertilization or combined application of nitrogen fertilize; The group CM₁ and CM₂ with adding organic material were greater than group C of the long-term single fertilization, but the group CM₂ was not greater than the group CM₁ in the same treatment. Long-term single application of chemical fertilizer could make the contents of AEC increase, especially the AEC of clay complex in NK fertilizing soils was the highest, and the matched group CK was the lowest, it was opposite to the rule of organic matter; The group CM₁ and CM₂ with adding organic material were less than group C of the long-term single fertilization, there was significant negative correlation with organic matter.The CEC_8.2 of the clay complex increased as the increasing of the pH value in the long-term application of chemical fertilizer soil, and decreased as the increasing of soil exchangeable acid, exchange of H⁺and exchangeable Al³⁺; Although CEC_P was significant positive correlation with pH, was no obvious correlation with soil exchangeable acid, exchange of H⁺ and exchangeable Al³⁺; The CEC_V was greatly influenced by soil pH, there was significant positive correlation with soil exchangeable acid, exchange of H⁺and exchangeable Al³⁺; The AEC was also influenced by soil pH greatly, was extremely significant negative correlation with pH, and significant positive correlation with soil exchangeable acid, exchange of H⁺and exchangeable Al³⁺; The CECm was uncorrelated with soil acidity and pH; The net negative change was extremely significant positive correlation with pH, the trend of soil acidification was greater, the net negative charge would be lower; The relationship between the surface charge density and soil acidity was accordance with the relationship between net negative charge and soil acidity, the surface charge density would increase when soil pH increased.Long-term fertilization of chemical fertilizer reduced the soil organic matter, and changed the surface properties of soil clay complex. Long-term single fertilization accelerated the trend of soil acidification, particularly the degree of soil acidification in single fertilization or combined application of nitrogen fertilize soil was on the high side, but adding organic material slowed down the trend of soil acidification.