入田泥沙对黄河三角洲地区土壤物理性状的影响——以小开河引黄灌区为例

为研究人田泥沙对小开河灌区自然土壤的影响，用分析化验和工程测试等方法，分析了引黄泥沙和输沙人田后土壤颗粒组成、容重、孔隙状况等物理性状。结果表明：引黄泥沙中0．02～0．002mm的细粉粒比例最高，平均39-31％。小开河自然土壤中0．05-0．02mm的粗粉粒比例最高，为53．41％，泥沙中细粉粒和粘粒含量明显高于当地土壤。输沙人田使灌区土壤中0．02—0．002mm的细粉粒和〈0．002mm的粘粒比例明显增加，〉0．02mm的颗粒比例下降，虽有效避免了因渠首集中沉沙造成的土壤沙化和生态环境恶化，但增加了土壤的粘重程度。农田耕作在一定程度上增加土壤通气孔隙比例、降低土壤容重，但土壤毛管孔隙度依旧稳定在40％左右，毛管作用旺盛，使土壤通气状况不能满足作物需求。在黄河三角洲地区输沙入田的泥沙处理，应结合当地土壤的基本性质和水盐运动规律配置泥沙，以免增强当地土壤紧实、通透性差的性状。

Effects of the sediment introduced into the field on Soil physical properties in Yellow River Delta-- A case study in Xiaokaihe Irrigation District

The effects of sediment coming from Yellow River water on the physical properties of field soil, including particle compo- sition, bulk density and porosity, are investigated on the specimens from Xiaokaihe irrigation district. The results of experimental testing reveal that for the sediment, the fine silt with radiuses ranging from 0.002 to 0.02 mm occupies 39.31 percent as the major component, while for the raw soil in Xiaokaihe irrigation district, the coarse silt with radiuses ranging from 0.02-0.05 mm occupies 53.41 percent as the major component. Thus, the introduction of sediment is able to definitely increase the fine silt and clay with radiuses lower than 0.02 mm and decrease the other components with greater radiuses, leading to enhanced sticky of the soil. This amendment of soil due to the sediment is beneficial to prevent soil desertification and ecological degradation. On the other hand, the amended soil subjected to regular cultivation for increasing aeration porosity and decreasing bulk density still has 40 % soil cap- illary porosity, under which the soil capillary strong and soil aeration can not satisfy the crop needs. This implies that an appropriate soil amendment method dependent on the sediment of Yellow River water in Yellow River Delta should synchronously take into account the relevant factors of soil properties and motional law of water and salt in soil.