Distribution Characteristics Of Soil Moisture In Pinus Sylvestris Var. Mongolica Plantations

Pinus sylvestris var.mongolica is the main tree species for constructing shelter forests in northern my country.The influence of its growth and development process on the changes of soil moisture is clarified,which provides a certain theoretical basis for the scientific management and sustainable management of Pinus sylvestris var.mongolica plantations.Using a combination of field surveys and laboratory analysis,the Pinus sylvestris var.mongolica plantations were selected as the research object,and a nearby control plot with the same land use pattern as before afforestation was selected to explore the changes in soil moisture and influencing factors of the Pinus sylvestris var.mongolica plantations in different forests on sandy land.On this basis,expand the scope of research,select mature forests as the research object,explore the distribution of soil moisture and influencing factors of Pinus sylvestris var.mongolica plantations in different climate areas,and infer the driving mechanism in soil moisture of Pinus sylvestris var.mongolica plantations in different climate areas.The results of the study are as follows:(1)The soil moisture of young forest of Pinus sylvestris var.mongolica on sandy land was higher than that of grassland;the change of soil water content of middle-aged forest and mature forest decreased gradually in the soil profile;the change of soil water content of over-mature forest showed an "S"-shaped curve.With the increase of stand age,the change of soil moisture in the 0?10 cm layer had no significant relationship with the stand age,and the 10?20 cm layer had a significant negative linear relationship with the stand age.The 20?100 cm layer showed a trend of decreasing first and then increasing.With the deepening of the soil layer,the change of soil moisture in the humid areas of Liaoning Province showed a downward trend,and the soil moisture in the semi-arid areas fluctuated greatly.The soil moisture in the forest land was higher than that of the control plot,and the humid areas were higher than the semi-arid areas.(2)Affected by changes in soil moisture,other physical and chemical properties of soil in forest land would change.The only influencing factors of soil moisture change of Pinus sylvestris var.mongolica forests in sandy land were soil alkali hydrolyzable nitrogen and soil available potassium,which are less affected by other physical and chemical factors.In humid areas,soil moisture changes were mainly related to soil phosphorus(total phosphorus,available phosphrous),soil organic carbon and soil p H.In semi-arid areas,soil moisture changes were mainly related to soil organic carbon and soil total phosphorus.In general,the establishment of Pinus sylvestris var.mongolica plantations can increase soil moisture content.However,semi-arid areas,as the age of forest stands increases,especially the middle-aged forest period,it was necessary to properly adjust the stand density to reduce the instability of the stand due to the lack of water and fertilizer in the Pinus sylvestris var.mongolica plantations,and maintained the normal growth and development of the forest stand.