江苏省低洼地区变性土的水分物理特征

Hydrophysical Characteristics of Vertisol in Lowland Areas of Jiangsu Province

本研究从剖面形态、粘土矿物及水分物理性质等方面，系统地揭示了江苏淮北东海县低洼地区砂姜黑土的土壤特征。该类土壤剖面结构因深度而变化，但是剖面的层次化却很弱，一般呈ＡＣ型剖面。粘土矿物以蒙脱石为多；各层土壤粘粒（小于０．００２ｍｍ）含量在４０％～６０％；线性膨胀系数（ＣＯＬＥ）为０．１４～０．１８。土壤膨胀收缩性能强，在旱作物种植季节，土表易生网状裂隙。江苏淮北低洼地区的砂姜黑土属于一种比较典型的变性土，这类土壤所显示的特征与全球变性土的性状十分类似。本文提供了在变性土上进行耕作试验的部分田间测定数据。我国在变性土上进行水旱轮作已３０余年，稻后旱作若能进一步推广少耕法，并结合秸秆盖田。

The morphology, mineralogy and physical properties of a Vertisol distributed in the lowland of Donghai County, Jiangsu Province, China are elucidated in the paper. The structure of the soil profile varied with depth, but the profile horizonation was weak, showing a AC profile.The soil clay minerals were dominated by the montmorillonites. The clay content(<0 002 mm) of this soil ranged at 40%-60%,and the coefficient of linear expansion (COLE) ranged from 0 14 to 0 18. Associated with the swelling and shrinkage of the soil, cracks were usually observed at the soil surface during the cropping season of dry crops.From the soil properties described here, it was considered that there existed a typical type of Vertisol in the lowland area of Donghai County, though it is classified as Shajiang black soil now in China.Some field experimental data dealing with the tillage management of the Vertisol are provided. It was noted that the yield potential of the post rice crops in that area might be great if some effective tillage management measures such as minimum tillage combined with straw mulch could be further extended.