单 位：
中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室;西安理工大学西北旱区生态水利工程国家重点实验室培育基地
关键词：
氮素;土地利用;氮素组成;相关性;汉江流域
摘 要：
氮素是土壤中不可或缺的营养元素之一,对植物生长具有至关重要的作用。利用网格采样法(30m×30m)和典型样地取样法在汉江余姐河小流域进行土样采集,每个样点分为3层A1(0—20cm),A2(20—40cm),A3(40—60cm),分别测定其土壤全氮、土壤铵态氮和土壤硝态氮含量。研究了土壤氮素的空间异质性、氮素的组成比例以及不同土地利用类型下土壤全氮、铵态氮和硝态氮与环境因子间的相关关系,并且分析了不同形态氮素间的相互关系。结果表明:土壤氮素的空间变异性为土壤硝态氮>土壤铵态氮>土壤全氮;土壤全氮与硝态氮在A1土层为强空间相关性,在A2,A3层为中等程度的空间相关性,土壤铵态氮在各土层均表现为中等空间相关性;农地、林地、草地对全氮储量的贡献依次增大;相较于林地草地,农地对铵态氮储量的贡献最大;而草地对硝态氮储量的贡献在三种土地利用中最大;不同土地利用类型中,农地的氮素空间分布主要与土壤粒径具有相关性,而与地形因子(坡度、坡向等)相关性较小;林地的氮素空间分布主要与地形因子相关性较高,草地介于两者之间;在流域内增加草地林地面积,在流域出口处布设林草地等措施可以减少流域土壤氮素的流失。
译 名：
Spatial Variability of Soil Nitrogen and the Impact Factors of Land-Use Types in Yujiehe Watershed,Han River
作 者：
ZHANG Zeyu;LI Zhanbin;LI Peng;XU Guoce;ZHANG Tiegang;Base of Eco-hydraulic Engineering in Arid Area,Xi′an University of Technology;State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Soil and Water Conservation,Chinese Academy of Sciences and Ministry of Water Resources;
关键词：
soil nitrogen;;land use;;composition of nitrogen;;correlation;;Han River
摘 要：
Nitrogen is an indispensable nutrient element in soil,and plays a vital role in the growth of plants.Grid sampling(30m×30m)and typical spot sampling were carried out in the study area,and soil samples were collected in three soil layers(0—20cm,20—40cm,40—60cm).Total nitrogen(TN),ammonium nitrogen(AN)and nitrate nitrogen content(NN)were determined.With classical analyses,geostatistical analyses,kriging interpolation,Pearson correlation analysis and Spearman correlation analysis,spatial variability of TN,AN,NN of land-use types and their correlations with environmental factors were studied.In addition,the relationships between different fractions of nitrogen were investigated.The results showed that soil nitrogen contents of the study area were at the low level;the TN,AN,NN contents decreased as soil depth increased;the spatial variability coefficient of NN was greater than AN,and both of them were larger than TN;the spatial dependence of TN and NN appeared to be high level in A1 layer and medium level in A2,A3 layers,and AN appeared moderate spatial dependence,which meant that the influence of human factors such as tillage on AN was greater than TN and NN,and it was the natural factor such as intrinsic properties of the soil and topography that controlled the distribution of TN and NN in A1 layer.The TN,AN,NN storage of the study watershed in 0-60 cm layer were 17.116 t,183.082 kg,62.528 kg,repectively;and the contribution ratio to TN decreased in the order:grassland>forestland>cropland;the contribution ratioof cropland to AN was larger than both grassland and forestland;grassland proved to have the biggest contribution ratio to NN among the three land-use types.The mean of AN/TN decreased as soil depth increased in cropland,but rose in grassland,and decreased in the sequence:A3>A1>A2;and the mean of NN/TN rose as soil depth increased in all the three land-use types.Pearson correlation analysis showed that AN/TN was highly significant positive correlated with NN/TN at a depth of 0—60cm(r=0.440,p<0.01);the correlations between different fractions of nitrogen were diverse in different layers and land-use types;Spearman correlation analysis indicated that nitrogen contents of cropland were mainly correlated with the soil particle size distribution,but was insignificantly correlated with topographic factors,nitrogen content of forestland had correlation with terrain factors.Therefore,increasing areas of forestland and grassland within the basin and the outlet can reduce the loss of soil nitrogen from catchment.
