长白山北坡土壤氮矿化时空分异特征

利用土壤温度连续观测数据,基于文献报道的土壤氮矿化测定数据,对长白山主要林型的年矿化量进行模拟计算,同时修正了以往利用气温计算造成的偏差以及相关模型中的参数错误.根据长白山各植被带的土壤温度观测数据,对各植被带的矿化量进行估计.位于基带的针阔混交林的矿化量为58.5 kg · hm-2 · a-1,红松云冷杉林为34.5 kg · hm-2 · a-1,岳桦云冷杉林为28.5 kg · hm-2 · a-1,苔原为19.6 kg · hm-2 · a-1.建立了通用于各植被带的土壤矿化对温度(t)的综合回归模型(y=0 038255e(0.1392t)).同时用所建立的综合方程,模拟计算了各海拔高度土壤氮矿化季节变化,并指出海拔每升高100m矿化速率降低2.31 kg · hm-2 · a-1.

Temporal and spatial variation of soil nitrogen mineralization in northern slope of Changbai Mountain in Northeast China

Soil nitrogen mineralization of the dominant vegetation types in Changbai Mountain, Northeast China, was simulated based on continuously observed soil temperature and published experiment data. Significant errors and biases, which were caused by unreasonable calculation and parameterization, in previous reports were verified. In this study, the nitrogen mineralization rates in different vegetation zones were estimated with temperature|dependent regression models. The mineralization rates were 58.5 kg?hm-2?a-1 in the conifer|broad leaf mixed forest which distributed in the foot of the mountain, 34.5 kg?hm-2?a-1 in the pine|spruce|fir mixed forest of subalpine, 28.5 kg?hm-2?a-1 in birch|spruce|fir mixed forest, and 19.6 kg?hm-2?a-1 in tundra. Based on the continuous records of soil temperature (t), an integrated regression model for estimating nitrogen mineralization rate (y, kg?hm-2?d-1), y=0.038255e(0.1392t), was established. The seasonal and vertical variation of nitrogen mineralization were also estimated with the regression model. The nitrogen mineralization was estimated to decline at a rate of 2.31 kg?hm-2?a-1 per 100m with elevation increase.