Changes of soil physical-chemical properties of Pinus tabuliformis plantations at different developmental stages in Ziwuling region of Loess Plateau

【Objective】This study illustrated the variations of soil properties of Pinus tabuliformis plantations at different developmental stages in Ziwuling region of Loess Plateau,aiming to improve soil maintenance in this region.【Method】The experiment was conducted in Zhongwan forest farm in Zhengning,Gansu using typical sample plots survey method.Slope wasteland was taken as control.The physical and chemical properties and contents of nutrients of the soil of Pinus tabuliformis plantations at different developmental stages(young forest,immature timber,nearly mature forest,and mature forest)were measured,and correlation analysis among all indicators was conducted.【Result】At different developmental stages of Pinus tabuliformis plantations,the change of soil moisture content was not significant.Soil bulk density and porosity of mature forest were better than those of other stages and the control.With the increase of the forest age,contents of soil organic matter and total nitrogen increased,while soil pH de-creased,and contents of available P,available K,nitrate and ammonium fluctuated.Correlation analysis showed that organic matter,total nitrogen and soil pH correlated with each other,with an extremely significant positive correlation between organic matter and total nitrogen,and a significant negative correlation between soil pH and total nitrogen or organic matter.【Conclusion】From the perspective of the soil sustainable development process,creating Pinus tabuliformis plantations in Ziwuling region of Loess Plateau could sustainably improve the soil physical-chemical properties and soil nutrients.