ABSTRACT

This study aimed to evaluate pedo-morphological properties to quantify the soil quality of alluvial soils in Indo-Gangetic Plains, India. In total, 241 geo-referenced soil profiles were collected representing four major landforms. The optimal scaling method was used to transform the categorical variables into numerical variables and the minimum datasets (MDS) were identified by categorical principal component analysis (CATPCA). Structure type and grade, texture class was highly loaded in PC 1 and explained about 36% of the variability. Four variables e.g. texture class, root quantity, structure size and hue were selected as MDS with 44%, 23%, 18% and 15% contribution to morphological soil quality index (MSQI), respectively. The MSQI of the study area varied 0.437–0.986 for surface and 0.110–0.989 for the sub-surface soils. The MSQI of alluvial landforms followed the sequence of old alluvial plain > young alluvial plain > meander plain > flood plain, respectively. The correlations of the selected pedo-morphological indicators were conducted and they were validated with laboratory data. In conclusion, landform-specific soil quality indicators were appropriate for the evaluation and monitoring of alluvial soils and MDS identified in this study could be effectively used to evaluate soil quality in a similar landscape with limited data.

摘要

本研究旨在评估土壤形态特性，以量化印度恒河平原冲积土的土壤质量。总共收集了代表四种主要地貌的 241 个地理参考土壤剖面。使用最佳缩放方法将分类变量转换为数值变量，并通过分类主成分分析（CATPCA）识别最小数据集（MDS）。结构类型和等级、纹理类别在 PC 1 中被高度加载并解释了大约 36% 的变异性。选择纹理类别、根数量、结构大小和色调四个变量作为 MDS，分别对形态土壤质量指数 (MSQI) 贡献 44%、23%、18% 和 15%。研究区的 MSQI 表层土壤为 0.437-0.986，地下土壤为 0.110-0.989。冲积地貌的MSQI依次为旧冲积平原>年轻冲积平原>曲流平原>洪泛平原。对选定的土壤形态指标进行了相关性分析，并用实验室数据对其进行了验证。总之，特定地形的土壤质量指标适用于冲积土的评估和监测，本研究中确定的 MDS 可以有效地用于评估类似景观中数据有限的土壤质量。