Effect Of Container Depth And Nitrogen Supply On Seedling Growth,Nutrient Storage And Field Performance Of Quercus Variabilis And Pinus Tabulaeformis

Nitrogen (N) supply and container type have individually proved to effectively manipulate seedling quality, however, their combined effects is rarely explored. Quercus variabilis, with its dominant taproot, and Pinus tabulaeformis, with its fabric root, were reared in two distinct depth containers with applications of either deficient or luxury nitrogen supply. Seedling growth, nutrient storage were measured at the end of first growing season, subsequently, survival, growth, nutrient remobilization were tested when seedling transplant with two contrasting soil fertility as well as outplant in two distinct weed condition site.In the nursery, For Quercus variabilis, optimum N loading (100mg N/seedling) facilated RCD, stem N and root K; deep container (36cm) increase seedling height, stem dry mass, stem K concentration and root K concentration as well as avoided root spiraling. For Pinus tabulaeformis, optimum N loading (80mg N/seedling) promoted aboveground growth, dry mass and nutrient content, however, decreased root growth; depth container (21cm) was beneficial to root growth and nutrient storage. The combination of optimum N loading and deep comtianer was conducitve to root N concentration of Quercus, and foliage P and K concentration as well as root growth potential of Pinus.In the pot experiment, under low soil fertility, 100mg N was favorable to current stem dry mass, N and K content, the same as perennial stem P content.36cm improve dry mass, P and K content. The combination of lOOmg N and 36cm facilated root, perennial and plant N content. Under different soil fertility,80mg N improved seedling dry mass and NPK storage both 60 days after transplanting and at the end of growing season of Pinus.21cm increased dry mass, perennial tissue NPK content, and current tissue K content. The combination of 80mg N and 21cm promoted seedling height, RCD, perennial stem P and K, as well as current tissue K of Pinus. However, the effects of combition of 80 mg N and 21cm on aboveground perennial tissue P and K were stricted to soil fertility.In the field experiment, For Qeurcus, 100mg N promoted RCD; 36cm increased seedling height, RCD, root dry mass, plant N and aboveground tissue P and K. The improvement of deep container on seedling stem and plant dry mass, stem N, root and plant K was affected by weed competation in the site. For Pinus,80mg N increased dry mass and NPK storage. The combination of 80mg N and 21cm improved seedling height and RCD, however these effects was limited to weed competation.Therefore, different soil fertility site and different weed competation site were considered holistically toward the effects of N supply, container depth and their interactions on seedling growth, nutrient storage and field performance. The optium combination of N supply and container depth was 100mg N/seedling and 36cm for Quercus variabilis, and 80mg N/seedling and 21cm for Pinus tabulaeformis.