关键词: 长期施肥, NO₃^--N累积层, 土壤水分布, 氮素回收率, 小叶章湿地, 氮沉降, 温室气体

Abstract: On the basis of long-term fertilization experiments in gully area of Loess Plateau, the relationships among fertilizations, NO₃^- -N accumulation, and moisture distribution in soil profiles were evaluated. The results showed that fertilization and rainfall significantly influenced the yields. NO₃^-- was accumulated in soil profiles under Nand Pfertilizers and organic manure(NPM) and Nand Pfertilizer (NP) treatment. The accumulated NO₃^--N reached 340kg·hm^-2 in 60～120cm under NPM treatment,and 220 kg·hm^-2 in 80～140cm under NP treatment, respectively. Soil moisture in 100～300cm was significantly reduced under NPM treatment. Under NP treatment,it was significantly reduced in dry year and normal year, while under organic manure(M) treatment, it was significantly reduced in dry year. Soil moisture under Pand CKtreatments was relatively stable in different years. Nuptake under NPM and NP treatments was significantly decreased in dry year. It reflected the close relationship among soil moisture, crops, and fertilization.

Key words: Long-term fertilization, NO₃^--accumulation, Soil moisture distribution, N uptake efficiency, Calamagrostis angustifolia wetland, nitrogen deposition, greenhouse gas