小五台山不同海拔土壤理化性质垂直变化规律

以河北小五台山不同海拔18块样地土壤为研究对象,分析和比较了不同海拔下土壤物理性质、持水能力、养分特征等14项指标,研究小五台山不同海拔土壤理化性质的垂直变化规律。结果表明:(1)随海拔的升高小五台山土壤容重逐步降低,总孔隙度逐步升高,毛管孔隙度变化不明显;随土层深度增加土壤容重变大,总孔隙度降低。(2)土壤含水量、毛管持水量、最大持水量、田间持水量随海拔升高逐渐升高,随土层深度增加逐渐降低,这种降低趋势随海拔增加逐渐扩大。(3)土壤有机质、全氮、全磷、碱解氮含量随海拔升高而逐渐升高,随土层深度增加而降低;土壤全钾含量随海拔升高表现为"先升后降"的抛物线型,在2 100～2 200m达到峰值。0—20cm土层速效钾和速效磷含量随海拔升高没有明显变化趋势;20—60cm土层速效钾含量随海拔升高而升高,40—60cm速效磷含量随海拔升高而降低。(4)土壤有机质、全氮、碱解氮含量有明显的"表聚现象",且海拔越高越明显;土壤全磷和速效钾含量也有明显的"表聚现象",海拔越高越不明显;土壤速效磷含量存在一定的"表聚现象",但并不明显;土壤全钾含量没有"表聚现象"。

Vertical Variation of Soil Physical and Chemical Properties at Different Altitudes in Xiaowutai Mountain

Taking 18 soil plots at different altitudes as the research object in Xiaowutai Mountain, Hebei Province, 14 indexes, such as soil physical properties, water-holding capacity and nutrient characteristics, were analyzed and compared to reveal the vertical variation of soil physical and chemical properties at different altitudes. The results showed that:(1) With the increasing of altitude, the soil bulk density gradually decreased, while the total porosity increased gradually, and the variation of capillary porosity was not obvious. As soil depth increased, soil bulk density increased and total porosity decreased. (2) Soil water content, capillary water-holding capacity, maximum water-holding capacity and field water-holding capacity increased gradually with the increasing of altitude, and gradually decreased with the increasing of soil depth, meanwhile this decreasing trend gradually expanded with the increasing of altitude. (3) The content of soil organic matter, total nitrogen, total phosphorus and alkali-nitrogen gradually increased with the increasing of altitude and decreased with the increasing of soil depth. The content of total potassium in soil was a parabolic type "first rising and then descending" with the increasing of altitude, and reaching its peak at 2 100~2 200 m. The content of available potassium and available phosphorus in 0-20 cm soil layer did not change obviously with the increasing of altitude. The content of available potassium in 20-60 cm soil layer increased with the increasing of altitude, while the content of available phosphorus in 40-60 cm soil layer decreased. (4) Soil organic matter, total nitrogen and alkaline nitrogen had obvious "surface aggregation phenomenon", and the higher the altitude, the more obvious it was. The content of total phosphorus and available potassium had obvious "surface aggregation phenomenon", and the higher the altitude, the less obvious it was. There was a certain "surface aggregation phenomenon" in soil available phosphorus content, but it was not obvious. Soil total potassium content had no "surface aggregation phenomenon".