关键词: 紫色土, 全氮, 速效氮, 土地利用, 坡位

Abstract: The study，based on the different slope position ( top，middle，bottom) and land use ( farmland，woodland， garden land and abandoned grassland)，analyzed the total nitrogen and available nitrogen in the soil. The results showed: ( i)the nitrogen content is influenced by the slope position，generally，the content of total nitrogen and available nitrogen is the highest in the bottom of slope，and the lowest content occurred in the middle of slope; (ii)the content of nitrogen is influenced by the land use，usually the content of total and available nitrogen in the woodland is the highest，and that in the farmland is the lowest;(iii)the ratio between carbon and total nitrogen is concentrated on 7. 3 ～ 13. 9 under different land use; (iv)the content of total nitrogen is correlated significantly with the bulk density，clay content，available nitrogen，total potassium and available potassium.

Key words: purple soil, total nitrogen, available nitrogen, land use, slop position