黑土区小流域土壤氮素空间分布及主控因素研究

Spatial distribution of soil nitrogen and its main driving factors in a mollisol watershed of China

在经典统计学和地统计学的基础上,结合＂3S＂技术,对黑土区海沟河小流域土壤表层（0~20 cm）中全氮（TN）、碱解氮（AN）的空间变异、分布特征及主控因素进行深入探讨.结果表明：海沟河小流域土壤TN含量处于较高水平,AN含量为中等水平;TN和AN的变程分别为900 m和1282 m,其空间变异均受地形、成土母质等结构性要素影响较大,在东-西（E-W）方向的空间变异相对剧烈;TN含量与坡度等地形指标显著性相关,AN含量与高程等地形要素显著性相关;回归协同克里格插值结果显示,TN自东向西呈现＂高-低＂交替的带状格局,与土地利用方式在东西方向上的演替相近,AN的高值在东部山区,低值在中部旱地分布集中的区域,呈现＂两边高,中间低＂的特征;水系、居民点等环境要素对TN和AN的空间分布存在明显的作用距离,土地利用方式及坡位对TN和AN含量分布影响显著,且存在较大差异.

In the study,classical statistics and geostatistics in combination with ＂ 3S＂ technology were used to investigate the spatial heterogeneity of total nitrogen（TN） and available nitrogen（AN）.Their main driving factors were analyzed at the surface soil layer of 0 ~ 20 cm in a mollisol watershed of China.The results indicated that,compared to the whole country,the content of TN was at a higher level,while AN was at a moderate level.The range of TN and AN were 900 m and 1282 m respectively,and their spatial variability were significantly affected by structural elements,e.g.terrain factors,climate and parent materials.There was a remarkable east-west gradient for both TN and AN.TN significantly was correlated with the slope,while AN had a significant correlation with height.The distribution map of TN was interpolated by regression co-kriging method,and the results showed that TN increased and then decreased,and the trends alternated from the east to west,which was similar to the spatial pattern of land use.Generally,AN was higher in the eastern mountains and lower in the central dry area,exhibiting ＂high at sides and low in the middle ＂characteristics.Obviously,the distributions of TN and AN were significantly influenced by the distance from residential area or river system.Furthermore,the distribution of TN and AN were also significantly influenced by the land use and slope positions,and the influence degree was spatially different