滨海沙地不同树种碳氮磷化学计量特征

Stoichiometric characteristics of carbon,nitrogen,and phosphorus in different tree species in a sandy coastal plain area

以滨海沙地尾巨桉、肯氏相思、纹荚相思、湿地松、木麻黄为研究对象,分别测定其新鲜叶片、凋落叶及0-10cm土壤层样品的养分含量,分析不同人工林碳氮磷化学计量比(C:N:P),探讨化学计量垂直分异特征.结果表明:C、N、P含量变化范围分别为叶片503.19-515.80、11.76-22.1、0.37-0.66 mg/g,凋落物474.81-497.28、7.18-15.54、0.34-0.55 mg/g,土壤3.41-4.41、0.33-0.47、0.09-0.12 mg/g;植物C、N、P含量显著高于土壤,不同物种间叶片N、P含量差异显著,凋落物C、N、P含量差异性显著.凋落叶C:N、C:P大于叶片但N:P小于叶片.植物N重吸收率大于P重吸收率(分别为29.54%、18.51%),且植物叶片N:P>16.本研究结果表明5个树种较大程度受到P元素限制,有助于更深入地认识滨海沙地养分循环规律和系统稳定机制.

The nutrient contents of fresh leaves, litter, and surface soil （0–10 cm） were determined in Eucalyptus urophylla × E. grandis, Acacia cunninghamii, A. aulacocarpa, Pinus elliottii, and Casuarina equisetifolia as the research objects, and the effects of the carbon, nitrogen and phosphorus stoichiometry （C：N：P） in different plantations were studied to explore the stoichiometric vertical differentiation characteristics. The results showed that the concentrations of C, N, and P were 503.19 to 515.80, 11.76 to 22.1, and 0.37 to 0.66 mg/g （leaves）; 474.81 to 497.28, 7.18 to 15.54, and 0.34 to 0.55 mg/g （litter）; 3.41 to 4.41, 0.33 to 0.47, and 0.09 to 0.12 mg/g （soil）, respectively. The C, N, and P contents of plants were significantly higher than those of soil. The concentrations of N and P in leaves of different species were significantly different. The concentrations of C, N, and P in litter were significantly different. The C：N and C：P ratios in litter were higher than those in leaves, but the N：P ratio was lower than that in leaves. The N resorption efficiency of plants （29.54%） was greater than the P resorption efficiency （18.51%）, and the leaf N：P ratio was greater than 16; these data showed that the tree species were mainly restricted by P. These results will contribute to a deeper understanding of the nutrient cycling law and the system stability mechanism of coastal sand.