干旱区生态环境知识资源中心

The knowledge of soil heterogeneity is useful for designing site-specific soil management practices especially for those affected by anthropogenic activities. The objectives of this study were to identify and select the dominating soil factors and attributes caused by wastewater application for the management decisions of West Mesa land application site using the principle component analysis. Variability in soil properties was identified by coefficient of variation (CV) as the indicator. A property was ranked as least (CV < 0.15), moderate (0.15 < CV < 0.35) or most (CV > 0.35) variable using the criteria proposed by Wilding. Nitrate (NO(3)(-)), chloride (Cl(-)), sodium adsorption ratio, saturated hydraulic conductivity, sodium (Na(+)), and electrical conductivity were most variable in the irrigated plots at the 0- to 20-cm depth. The principle component analysis, which is widely used to reduce the dimensions of data, grouped 15 soil physical and chemical properties into four components (eigenvalue >1) soil sodicity, water transport, soil texture, and organic matter at the 0- to 20-cm depth and soil sodicity, soil texture, water retentiona and organic matter at 20- to 40-cm depth. Redundancy analysis showed that soil sodicity factor and Na(+) as the most dominantly measured soil properties at both depths. Therefore, Na(+) should be monitored over time in the West Mesa land application site. The mean sodium adsorption ratio for study site was 19.17 +/- 2.92 in the irrigated plots, which is above the threshold limit for many plant species and may threaten the survival of woody and perennial herbaceous vegetation in the study area. Therefore, it is necessary to initiate management strategies for controlling soil sodicity in the West Mesa land application site.