A Study On Nutrients And Root Architecture Of Different Aged-cunninghamia Lanceolata And Larix Principis-rupprechtii Mayr Plantations

The characteristics of nitrogen (N) and phosphorus (P) accumulation, the characteristicsof root distribution and the correlation between the plant nutrient and root architecture, theplant nutrient and soil nutrient, soil nutrient and root architecture were discussed through theanalyze of total N, P in soils and in root, stem and leaf tissues, root architecture and plantbiomass of different aged-Cunninghamia lanceolata and Larix principis-rupprechtii Mayrplantations. Confirm the root architecture of C. lanceolata and larch and reveal thecharacteristics of NP distribution and accumulation. This provided the reference for operatingand managing the Cunninghamia lanceolata and Larix principis-rupprechtii Mayr plantations.The main results were summarized as follows:N and P concentrations in soils under the C.lanceolata plantations decreased with theincrease of soil depth. Concentrations of total N in soils elevated with increases in ages ofplantations. There was no significant difference in concentrations of total P in soils withdifferent ages of plantations.The order of N concentrations in different organs was leaves> stem> coarse roots> fineroots. N concentrations in different organs elevated with increases in ages of plantations. TheN and P concentrations were higher in fine roots, coarse roots and leaves and lower in stem.Concentrations of total N in coarse roots and stem elevated with increases in ages ofplantations. The accumulation of N and P in different organs increased with increases in agesof plantations. The order of the accumulation of N and P of10-year-old plantations and theaccumulation of N of10-year-old plantations was leaves> roots> stem. The order of theaccumulation of P of20-year-old plantations and the accumulation of N and P of30-year-oldplantations was roots>leaves>stem.There was no significant difference in specific root length and specific surface area infine root of different aged-C.lanceolata plantations. Root tip density and forks of20-and30-year-old plantations were significantly higher than that of10-year-old plantation. Totallength of coarse roots, mean length of proximal roots, diameter of proximal roots, radialdistance and root depth were increased with increases in ages of plantations, the number of proximal roots were decreased with the ages.A significantly positive linear correlation was observed between the concentrations of Nin fine roots and specific root length, specific surface area and forks. The concentrations of Pin fine roots and root tip density assumed remarkable being related. There was a significantpositive correlation between the concentrations of N in coarse roots and mean length ofproximal roots. A significantly positive linear correlation was observed between theconcentrations of P in coarse roots and parameters of coarse roots architecture. Except the10-20cm layer. There was a significant positive correlation between the concentrations of Nin other soil layers and parameters of coarse root architecture.N concentrations in soils under the larch plantations decreased with the increases of soildepth. Concentrations of total N in soils decreased with increases in ages of plantations. Theconcentrations of P in soils of5-and20-year-old plantations decreased with increases in agesof plantations. The concentrations of P in soils of10-year-old plantations were higher thanthat of5-and20-year-old plantations.The order of N and P concentrations in different organs of larch was leaves> fine roots>coarse roots> stem. The N and P concentrations in fine roots, coarse roots, stem and leavesdecreased with increases in ages of plantations. The accumulation of N and P in differentorgans increased with increases in ages of plantations. The order of the accumulation of N of10-and20-year-old plantations was leaves> roots>stem. The order in5-year-old plantationswas leaves> stem> roots. The order of the accumulation of N of all the three plantations wasleaves> stem> roots.Specific root length and specific surface area of fine root of different aged-larchplantations decreased with increases in ages. There was no significant difference in root tipdensity and forks. Except the number of proximal roots, all the parameters of coarse rootsarchitecture increased with increases in ages of plantations.The concentrations of N and P in fine roots, coarse roots and stem assumes remarkablebeing related. A significantly positive linear correlation was observed between the N, Pconcentrations of fine root and Specific root length and specific surface area of fine root.There was a significant positive correlation between specific root length, specific surface areaand the concentrations of N in10-20cm layers. The concentrations of N in0-10cm layersand forks showed a significant negative correlation. A significantly negative linear correlationwas observed between the N, P concentrations of fine root and parameters of coarse rootarchitecture. There was a significant negative correlation between total length of coarse roots, mean length of proximal roots, radial distance and the concentrations of N in0-20cm layers.The concentrations of N in0-20cm layers and root depth assumed remarkable inversecorrelation. The concentrations of P in40-60cm layers and root depth showed a significantpositive correlation.