不同施肥制度下褐土微团聚体内氮素肥力的变化规律

Changes of Nitrogen Fertility in Cinnamon Soil and Its Micro-aggregates under Different Fertilization Systems

通过8年定位试验,研究了不同施肥制度下褐土及其微团聚体氮素肥力变化规律,从各级微团聚体全氮和碱解氮储量角度探讨了不同施肥制度下土壤氮素肥力的变化实质。结果表明:不施肥处理由于10～50μm粒级全氮储量和<10μm粒级碱解氮储量降低(分别减少51.8mg.kg-1和31.4mg·kg-1),而造成土壤氮素肥力下降;单施常量NPK化肥和增量NPK化肥处理通过提高<10μm粒级碱解氮储量(分别上升5.7mg·kg-1和9.3mg.kg-1),增加土壤碱解氮含量;有机肥(物)料配施常量NPK化肥处理则通过增加大粒级特别是10～50μm粒级全氮和碱解氮储量(分别上升41.2～69.7mg.kg-1和8.0～9.2mg·kg-1),而使土壤氮素肥力水平得到提高。采用有机肥(物)料配施常量NPK化肥是改善褐土氮素肥力的有效措施。

Eight years＇ location experiment was conducted in cinnamon soil in Hebei to study the changes of nitrogen fertility in soil and its micro-aggregates, and to study the changes of the soil nitrogen fertility under different fertilizatior regimes from the view points of the storage of total N and alk-hydrolysable N in various micro-aggregates. The results showed that no fertilization rduced mainly the storage of total N in 10-50μm and alk-hydrolysable N in 〈10μm micro-aggregates （reduction of 51.8 mg·kg^-1and 31.4mg·kg^-1, respectively）, and resulted in soil nitrogen fertility decrease. Application of usual and increment NPK fertilizers enhanced mainly the storage of alk-hydrolysable N in 〈10μm （increase of 5.7mg·kg^-1,9.3 mg·kg^-1, respectively）, and increased the content of total N.Application of organic manure combined with usual NPK enhanced the storage of total N and alk- hydrolysable N, especially in 10-50μm micro-aggregates （increase of 41.2 mg·kg^-1 - 69.7 mg·kg^-1and 8.0 mg·kg^-1 - 9.2 mg·kg^-1, respectively）, and improved soil nitrogen fertility.