西北荒漠区土壤氮素组分沿干旱梯度的空间变化

杭伟, 陆永兴, 郭浩, 郭星, 张世航, 张元明, 周晓兵

Spatial variation in soil nitrogen content along aridity gradients in the northwest desert region in China

Wei Hang, Yongxing Lu, Hao Guo, Xing Guo, Shihang Zhang, Yuanming Zhang, Xiaobing Zhou

图4 全氮、铵、硝态氮及其比例对干旱指数和土层的响应模型 注：曲虚线为广义相加模型（GAM）拟合的平滑趋势线，分别为各阈值左右两侧的线性拟合。直线为拟合线性模型拟合的趋势线，垂直虚线表示阈值。干旱指数为1-AI， AI为降水量与潜在蒸散量的比值

Fig.4 Response model of total nitrogen，ammonium，nitrate nitrogen and their ratio to drought index and soil depths