Root System And Soil Nutrient Distribution Of Pinus Sylvestris Var.mongolica Plantation On Sandy Land Feature Research

Root system could affect the physical and chemical properties of the soil.The growth and distribution of the root system were of great significance to the growth and development of Pinus sylvestris var.mongolica.In order to explored the relationship between roots distribution,root nutrient content and root ecological stoichiometry of Pinus sylvestris var.mongolica,the root system distribution,soil nutrient content and soil ecological stoichiometry at different horizontal distances from tree trunk(0 m,0.5 m,1.0 m,1.5 m,2.0 m),different soil layers(0?20cm,20?40 cm,40?60 cm,60?80 cm,80?100 cm),different directions(South,North)were studied of Pinus sylvestris var.mongolica in Horqin Sandy Land 10 a,40a and 60 a,and provided a theoretical basis for the sustainable management and evaluation of Pinus sylvestris var.mongolica plantation in sandy land.Research indicates:(1)Comparied between different orientations,the number of young forest roots in the south was higher than north,the mature forests and over-mature forests in the north were higher than the south;the young forest and mature forest roots in the north were higher than the south,and the over-mature forests south was higher than north.The number and diameter of root systems of Pinus sylvestris var.mongolica in various forest ages decrease with the increase of the depth of the soil layer and the horizontal distance.The root systems were mainly distributed in the surface soil and near the trunk.With the depth of the soil layer,the roots were mainly concentrated in the top soil layer(0?40 cm),and in the horizontal direction from 0?0.5 m from the trunk.(2)With the increase of soil depth,the nutrients in the root soil of Pinus sylvestris var.mongolica in young forest,mature forest and over-mature forest showed a decreasing trend.,and have super aggregation,and each nutrient is concentrated in the surface layer(0?20 cm)soil.Comparied different orientations,the different nutrients of different forest ages had different heights in the north and south.In general,the soil organic matter,total nitrogen,available nitrogen,total phosphorus and available phosphorus in the roots of Pinus sylvestris var.mongolica.The content of organic potassium and available potassium were higher than that in the north;the content of organic matter,total nitrogen and available potassium in the roots of mature forests was higher in the south than in the north;The content of organic matter,available phosphorus,total potassium and available potassium in the roots of over-mature forests was higher in the different direction.With the increase of forest age,the contents of soil available nutrients(available nitrogen,available phosphorus and available potassium)in roots of Pinussylvestris var.mongolica showed a decreasing trend.The contents of soil organic matter and total potassium increased first and then decreased,total nitrogentotal and phosphorus content was slowly increasing.(3)The soil C: N in the young and mature forests of Pinus sylvestris var.mongolica was higher than the national average value of soil C: N,and the soil N availability was less,which was shown as nitrogen limitation.In the young forest,near the trunk,and in the mature forest,far from the trunk,the soil nitrogen is more restricted.The N: P soil Pinus sylvestris var.mongolica was far below the national level.It further showed that the soil of Pinus sylvestris var.mongolica forest was restricted by N.