黄土高原沟壑区原状土壤氮素迁移

以中国生态系统研究网络CERN长武王东沟实验站的坡耕地和塬耕地为供试土壤,研究了黄土高原沟壑塬区旱耕地原状土壤氮素迁移和时空变异。结果表明:耕作土壤NO3--N为23.1~33.8 mg/kg,NH4+-N为0.23~0.50mg/kg,DOC为9.17~13.38 mg/kg,P为0.18~0.23 mg/kg;坡耕地和塬耕地的NO3--N和NH4+-N主要集中在0~20 cm的上层土壤,中下层土壤NO3--N和NH4+-N起源于上层淋溶迁移和累积;高含量时养分淋溶溶出呈指数衰减型;NO3--N、NH4+-N、DOC向下层的迁移塬耕地慢于坡耕地。

Nitrogen Migration in Intact Soil of Hilly-gully Region of Loess Plateau

Plateau cultivated soil and gully cultivated soil from the northern part of Wangdong hilly-gully region in Changwu lab-station of CERN was used as research soil.The nitrogen migration and its time-space variation of intact soil core in arid agriculture ecosystem in loess plateau were studied.The results are: the content of NO3--N was from 23.1 to 33.8 mg/kg,NH4+-N from 0.23 to 0.50 mg/kg,DOC from 9.17 to 13.38 mg/kg,P from 0.18 to 0.23 mg/kg.In arid cultivated soil,NO3--N and NH4+-N mainly concentrate in top-layer of the soil from 0–20 cm.NO3--N and NH4+-N in the mid-and low-layer of the soil migrated from leaching accumulation of top-layer soil.Migrating rate of NO3—N,NH4+-N,DOC from top-layer to low-layer of soil in plateau cultivated soil is slower than that in gully cultivated soil.