滨海地区暗管排盐工艺下洋白蜡行道树养分特征

Nutrient Characteristics of Fraxinus pennsylvanica Street Trees under the Technique of Subsurface Drainage in Coastal Area

暗管排盐工艺技术下的洋白蜡行道树根系生长在厚1m、宽1.2m的长条形土壤空间中,植物生长可能发生营养缺失。文章对不同林龄洋白蜡行道树土壤和植物叶片养分特征进行了测定,结果表明:在每年基施肥料养护措施下,林龄越大(即建植养护时间越长)的洋白蜡行道树绿地土壤有机质、N、P等养分含量明显越高,且不同林龄绿地土壤养分含量都随土层深度的增加而明显降低;不同林龄洋白蜡叶片有机C、N含量无明显差异,N/P在8.64～11.29之间,P与N比较相对含量高;为了保证洋白蜡持续健康生长,应当增加施肥深度,改善中下层土壤水肥条件,促进根系向下生长,同时适当增加N施用量、减少P施用量。

Under the condition of subsurface drainage,Fraxinus pennsylvanica street trees have their root system refined in the strip soil space at 1 m thick and 1. 2 m wide,and the nutrient deficiency might occur during their growth. The paper studies the nutrient characteristics of soil and leaves of F. pennsylvanica street trees at different ages. The results indicated that the older the street trees are,the higher the contents of the soil organic matter,N and P are,under the annual application of base fertilizer,and the content of soil nutrients in forests at different ages decreased with the increase of soil depth. The C and N contents in leaves of trees at different age showed no significant variation,and N/P ratios were between 8. 64 and 11. 29,indicating that P was relatively higher in content than N. In order to ensure the sustainable and healthy growth of F. pennsylvanica street trees,it is proposed to apply the base fertilizer to the lower soil layers,improve the moisture and fertilization condition of deep soil,and promote the downward growth of root system,while increasing N content and reducing P content in the base fertilizer.