A Study On Soil Physical And Chemical Properties Of Typical Forests In The Liaoheyuan Area Northern Of Hebei Province

The characteristics of soil physical and chemical properties at different ages and the layer deepening was studied in Pinus tabulaeformis、Populus davidiana natural secondary forest plantation in Hebei Province, Liaoheyuan Nature Reserve Pinus tabulaeformis、Populus davidiana natural secondary forest to explore the impact of forest ages on the soil physicochemical characteristics. The results show that:(1) With the increase of forest age, soil moisture and soil total K content decreased first and then increased gradually. Soil bulk density reduced steadily while soil pH and soil total P content increased slightly, respectively. Soil organic matter and soil total N content increased first and then decreased significantly. Variance analysis and multiple comparison results show that the stand age has non-significant effects on soil physical properties but considerable effects on soil chemical properties in different soil layer.(2) In the0～100cm soil layer, the soil bulk density (1.32～1.68g·cm-3) and soil pH content (6.02～6.64) increased with the soil layer deepening while the soil moisture (4.38～20.18%), soil organic matter (4.32～28.10g·kg-1), soil total N (0.12～1.64g·kg-1), soil total P (0.19～0.71g·kg-1) and soil total K (3.63～4.51g·kg-1) suppressed the rate of increase with the soil layer deepening of every forest age.(3) Correlation analysis showed that in addition to soil total P content has none-correlation between physical and chemical properties, and the correlation coefficient of the positive and negative correlation was more complicated.(4) With the increase of forest ages, Populus davidiana showed mature forest> nearly mature forest> middle-aged forest on soil total K content(4.32～4.72g·kg-1) and soil bulk (1.07～1.69g·cm-3) in0～100cm soil layer of, whereas middle-aged forest> nearly mature forest>mature forest on soil moisture (7.35～24.39%). Soil total N content (0.28-2.76g·kg-1) and soil total P content (0.46-1.37g·kg-1) increased first then decreased gradually from high to low as nearly mature forest>mature forest>middle-aged forest, while soil pH (5.03-5.98) decreased first and then increased significantly that was mature forest> middle-aged forest>nearly mature forest. The soil organic matter (2.64～31.99g·kg-1) fluctuated according to the forest age in0～20cm soil layer that was nearly mature forest>mature forest> middle-aged forest but its had the contrary tendency in20～100cm soil layer.(5) The soil pH increased firstly and then decreased gradually, the soil bulk density and soil total K content increased with the soil layer deepening while the soil moisture, soil organic matter, soil total N, soil total P and soil total K suppressed the rate of increase with the soil layer deepening of every forest age.(6) Correlation analysis showed that there was a correlation between each physical and chemical indexes in different level, the soil moisture had a negative correlation with soil bulk density while had a positive correlation with soil organic matter and soil total N. The soil bulk density had a negative correlation with soil organic matter and soil total N. The soil pH had a negative correlation with soil total K. The soil organic matter had a positive correlation with soil total N but a negative correlation with soil total K. The soil total N had a positive correlation with soil total P but a negative correlation with soil total K. The soil total P had a negative correlation with soil total K.