黄土区不同土壤类型及土地利用方式对土壤氮素矿化作用的影响

Effects of the different soil types and landuse on nitrogen mineralization on the Loess Plateau

采用室内培养试验研究了黄土区不同类型土壤（黑垆土、红油土和淋溶褐土）及土地利用方式（农田、林地）的氮素矿化特性。结果表明，3种土壤好气培养0～14，15～28和0～28d的氮索矿化量、矿化速率与矿化率大小次序均为：淋溶褐土〉红油土〉黑垆土；林地黑垆土氮素矿化量和矿化速率极显著地高于农田黑垆土；淹水培养7d，3种土壤矿化氮量、矿化速率和矿化率大小次序均为：红油土〉淋溶褐土〉黑垆土，但差异不显著;淹水培养条件下，林地黑垆土氮素矿化量、矿化速率和矿化率均高于农田黑垆土。不同土地利用方式对土壤氮素矿化作用的影响强于不同土壤类型的影响。

The characteristics of the nitrogen mineralization of three typical soils including Isohumisols,Anthrosols and Argosols on Loess Plateau were evaluated by the aerobic and anaerobic incubation methods. The amount of mineralized nitrogen （AMN） and its mineralized rate per day of incubation （RPD） or mineralized ratio of the total soil nitrogen （RTS） of the three soils followed the order of Argosols〉An- throsols〉Isohumisols, during the aerobic incubation of 0--14,15--28 or 0--28 days. Under the same Isohumisols with different vegetations, the AMN and RPD of the forest soil were significantly higher than that of the arable soils. When the soils were incubated in anaerobic condition for 7days, the AMN, RPD and RTS of the soils followed the order of Anthrosols 〉 Argosols 〉Isohumisols, but the differences among the soil types were not significant. Under the same Isohumisols with different vegetations, the AMN, RPD and RTS of the forest soil were significantly higher than those of the arable soils. These results indicate that the vegetation has stronger effect on soil nitrogen mineralization than soil types.