水曲柳人工林土壤养分的空间异质性研究

Study on Spatial Heterogeneity of Topsoil Nutrient in Fraxinus Mandshurica Plantation

采用地统计学的变异函数分析方法，定量研究了14年生水曲柳人工林表层土壤（0～10cm）养分的空间异质性特征。结果表明：（1）土壤有效磷、全钾和速效钾变异函数曲线的理论模型符合指数模型，土壤pH值符合球状模型，土壤全氮、水解氮和全磷的理论模型符合指数模型或球状模型；（2）土壤养分各项指标的空间变异主要是由结构性因素引起，且空间自相关程度均属中等以上（空间结构比均在25％以上）；（3）土壤pH值的空间自相关范围最大（2．27～4．46m），土壤全磷的自相关范围（0.73～0．97m）小于全钾和全氮（分别为1．02～1．05m和0．90～1．18m），土壤有效磷的自相关范围（0.90～1．20m）小于速效钾（0.95～2．86m）和水解氮（1．41～4．25m），速效养分的自相关范围均大于或近似等于相应养分的全量养分。（4）土壤pH值、氮、磷和钾素的空间格局明显，土壤pH值、全氮、水解氮、全磷、有效磷、全钾、速效钾的分数维分别为1．789～1．862，1．217～1．952，1．838～1．927．1．878～1．935，1．899～1．944，1．936～1．965，1．907～1．963。

Semivariance analysis of Geostatistics was employed in the quantitative study of the spatial heterogeneity of nutrient in upper layer of soil （0～ 10 cm ） under 14-year-old Fraxinus mandshurica plantation. The results showed that （1） the semivariograms of available phosphorus, total potassium and available potassium in topsoil were best described by spherical model, that of soil pH submitted exponential modal, and those of total nitrogen, available nitrogen and total phosphorous submitter spherical or exponential models. （2） The spatial variability of soil nutrient was primarily the result from structural factors, and the spatial heterogeneity degree of those indices was moderate above （with spatial structural ratio above 25%）. （3） the scale of spatial heterogeneity of pH in topsoil was highest （2.27～4.46 m）, that of total phosphorous （0. 73～0. 97 m） was smaller than that of total potassium and total nitrogen （1.02～1.05m and 0. 90～ 1.18 m, respectively）, that of available phosphorous was smaller than that of available potassium and available nitrogen（0. 95～2.86 m and 1.41～4. 25 m, respectively）, and that of available nutrient was higher or approximately equal to that of total nutrient of corresponded element. （4） the spatial pattern of pH, nitrogen, phosphorus and potassium in topsoil was evidence, the fractal dimension of pH, total nitrogen, available nitrogen, total phosphorus, available phosphorus, total potassium and available potassium in topsoil of Fraxinus mandshurica plantation was1. 789 ～ 1. 862, 1. 217 ～ 1. 952, 1. 838 ～ 1. 927, 1. 878～1. 935, 1. 899～1. 944, 1. 936～1. 965 and 1. 907～1. 963, respectively.