水蚀风蚀交错带土壤-植被系统氮素空间变异特征  

Spatial Variability of Nitrogen in Crisscross Region of Plant-Soil System of Water-Wind Erosion

作　　者：高海龙[1,2] 王辽宏[1,2] 张兴昌[1,2] 

机构地区：[1]西北农林科技大学资源环境学院,陕西杨凌712100 [2]黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨凌712100

出　　处：《水土保持通报》2014年第2期281-286,共6页Bulletin of Soil and Water Conservation

基　　金：国家自然科学基金项目"水蚀风蚀交错带典型小流域自然梯度下生源要素循环特征"(40801111);西北农林科技大学基本科研业务费(QN2011147);中国科学院西部行动计划项目(KZCX2-XB3-13)

摘　　要：采用经典统计学和地统计学相结合的方法,分析了黄土高原水蚀风蚀交错带本氏针茅草坡地土壤—植物系统氮素沿坡面的分布,并从不同空间尺度研究了土壤—植物系统氮素的空间结构特征,以揭示水蚀风蚀交错带草坡地土壤—植物系统氮素分布特征。研究结果表明,随坡位的降低,草坡地植物生物量、植物氮含量和储量均逐渐增加;土壤有机质和全氮含量在坡上部和坡中部相近,但均低于坡底部;土壤硝态氮和铵态氮含量沿坡面呈先降低而后在坡底部迅速增加的变化趋势。这些变量的变异系数除硝态氮和铵态氮以坡中部最小外,均以坡底部最小,表明坡底部土壤—植物系统氮素分布最为均匀。各变量的最佳拟合模型在3个分析尺度上均保持一致,且随分析尺度的增加,块金常数、块金效应逐渐增大,样点间的空间依赖性逐渐减弱,空间相关性减弱。表明水蚀风蚀交错带草坡地土壤—植物系统氮素在不同尺度上空间结构比较稳定,属中等或强空间相关性,其空间变异主要来源于结构性因素。Traditional statistics,combined with geostatistics,were applied to analyze the spatial distribution of nitrogen（N）in plant and soil on a Stipa bungeana slope in the water—wind erosion crisscross region of the Loess Plateau.The spatial characteristics of the plant—soil system at different spatial scales were studied to reveal characteristics N distribution in the region grassland.Results showed that plant biomass,plant N content,and N stock increased gradually with the decrease of slope position.Soil organic carbon and nitrogen content in the upper and middle positions were similar,lower than those in the bottom position.Soil nitrate nitrogen and ammonium nitrogen contents performed a V-shaped change,with the highest content being on the upper slope.Except nitrate nitrogen and ammonium nitrogen contents,the variation coefficients of those variables measured to be the lowest on the bottom slope,which indicates that N distribution of plant—soil system was uniform on the bottom slope.Furthermore,the best fit models for each variable were precisely consistent at the three scales.Nugget effect increased,while spatial dependence between different sample points and spatial correlation weakened gradually with the increase of analysis scale.These results indicate that N in plant and soil have relatively stable spatial structures at different spatial scales and are characterized by medium or strong spatial correlation,and its spatial variation is mainly caused by structural factors.

关 键 词：水蚀风蚀交错带 本氏针茅草坡地 土壤—植物系统 氮素空间变异 

分 类 号：S158.2[农业科学—土壤学]