沱江中游土壤有效铁空间分布及其影响因素分析

Soil Available Iron Spatial Distribution and Influencing Factors Analysis Based on GIS in Middle Reaches of Tuojiang

本文采用ArcGIS、地统计学及统计分析方法,研究了沱江中游耕层(0～20 cm)321个土样的土壤有效铁含量的空间分布特征及其影响因素。结果表明,沱江中游土壤有效铁含量平均为(20.71±26.17)mg.kg-1,达到一级,其含量属于丰富。土壤有效铁含量整体主要呈条带状分布,局部出现斑点、块状区域,高值区分布在西北部的清江镇附近,低值区分布在西南部的五凤镇和东南部的金龙镇附近。影响因素分析表明,土壤有效铁含量与pH呈极显著负相关,与有机质含量呈极显著正相关。土地利用方式和土壤质地发生改变时,土壤有效铁含量随之改变,中壤土与灌溉水田中有效铁含量最高,而砂壤土与有林地中最低。随着坡度的升高,土壤有效铁含量呈降低的趋势。

This article used the geographic information systems, geostatistics and statistical analysis method to study the soil available iron spatial distribution characteristic and the influencing factors of the topsoil （0 -20 cm）321 soil samples in the middle reaches of the Tuo- jiang,the results showed that the average of soil available iron were 20.71 ± 26.17mg kg＂l ,and reached the first level ,the content belonged to be rich, soil available iron content mainly took on annular distribution,partial spot and plump, and soil available iron content of high-value areas were located in the northwest near the town of Qingjiang, low-value distribution of Wnfeng Township in the southwestern and southeast near the town of the Jinglong. The soil available iron content elevated along with pH reducing, soil avaibale iron and pH was highly signifi- cant negative correlation; soil iron and organic matter content was highly significant positive correlation. As land use types changed, the ef- fective iron content in the soil changed; as the gradient increased, the soil available iron content assumed decreasing trend.