泰山山前平原三种土地利用方式下土壤结构特征及其对土壤持水性的影响

不同土地利用方式因其植被和管理方式差异影响土壤结构特征而改变土壤持水性。选择泰山山前平原农田、林地和荒草地3种土地利用方式,分析不同土壤颗粒组成、颗粒粒径分布与团聚体组成及其水稳定性等土壤结构特征指标,利用原状土样测定,结合土壤水分特征曲线分析土壤持水量、持水强度及水分有效性,通过逐步回归与通径分析明确影响土壤持水性的主要结构特征指标。结果表明,与荒草地相比,农田和林地显著提高了土壤粘粒含量、有机碳含量、土壤毛管孔隙度,降低了土壤容重、> 2 mm水稳性团聚体含量及团聚体的水稳定性。农田土壤的细颗粒组成含量和颗粒比表面积显著高于林地和荒草地土壤。土壤饱和含水量的大小依次为农田>林地>荒草地,农田土壤的田间持水量为31%,分别比林地和荒草地高15%、24%。土壤容积含水量θ与吸力S之间的关系符合幂函数方程θ=A·S^-B（系数A、B为常数,A值表征土壤持水强度,大小依次为农田>林地>荒草地）。土壤有效水总量与速效水含量大小依次为林地>农田>荒草地。逐步回归与通径分析表明土壤粘粒含量通过直接和间接作用增强土壤持水性,土壤颗粒比表面积和水稳性团聚体的平均重量直径对土壤持水性的影响主要体现在间接作用,土壤水稳性团聚体的平均重量直径是抑制土壤持水性的关键因素。土壤有机碳含量对调节土壤粘粒含量和土壤水稳性团聚体形成具有重要作用。因此,在该区土地开发利用过程中,以提高土壤有机碳含量改善土壤结构性质为原则,建议土地利用方式以农业与林业轮作或间作措施为主,合理开发荒草地,为该区土壤水分管理与土地可持续开发利用提供参考依据。

Soil Structure and Its Effect on Soil Water Holding Property under Three Land Use Patterns in Piedmont Plain of Mountain Tai

Soil water holding capacity, which is controlled by soil structure properties of land uses types with different vegetation and management systems, plays an important role in soil fertilization and crop root development. This study is to explore changes of water holding capacity and soil physicochemical properties in three land use types in piedmont plain of Mountain Tai, such as soil particle composition, particle size distribution, water stable soil aggregate content. Original soil samples in agricultural soil, forest field and barren land in meadow brown soil region and soil water characteristics curves were used to inspect soil water holding capacity, soil water and soil moisture holding, and supply capacity. The soil physicochemical properties affecting soil water holding capacity were identified by step regression and path coefficient method. Results showed that the agricultural soil and forest field had significant higher clay content, organic carbon content and soil capillary porosity and lower aggregate stability than barren land. Agricultural soil had more composition of fine particles and surface area of soil particles than forest field and barren land. The order of field water holding capacity from high to low was agricultural soil, forest field and barren land, which was 31% in agricultural soil and was 15% and 24% more than those in forest field and barren land. There was a power function correlation between the soil moisture and the potential of soil water, which is θ=A·S^-B. The value A indicates the intensity of soil water retention with the order from high to low of agricultural soil, forest field and barren land. The order of total available water content and rapid available water percentage from high to low was forest field, agricultural soil and barren land. Step regression and path analysis indicated that soil water retention intensity was positively correlated with soil specific surface area and clay contents and was negative correlated with the stability of soil aggregates. Soil organic carbon played an important role in controlling soil clay content and soil aggregate formation. Consequently, the organic matter input should be increased in order to ameliorate soil structure, and rotation and intercrop should be applied in agricultural and forestry farming in order to improve soil water retention properties. The outcome of this paper provides reference for keeping soil fertility and sustainable application in the region of brown soil.