园林绿地常见针叶树叶养分利用及回流特点

以合肥市常见的6种针叶树种为对象，就其针叶养分(包括氮、磷、钾、钠、钙、镁等)含量及其回流特点进行了分析。结果表明，不同树种叶养分利用效率及回流率存在一定差异。所测的养分中，磷的利用效率和回流率最高，分别是461~4 495 g/g和5%~64%；其他元素依次为钾(215~567 g/g和13%~64%)、氮(62~114 g/g和10%~40%)、钠(364~424 g/g和7%~24%)、镁(214~316 g/g和-57%~12%)；钙的利用效率较低(43~73 g/g)，并在落叶中富集。不同树种中磷和钙的利用效率之间存在极显著正相关，氮和钠之间存在显著正相关；而各养分利用效率与立地土壤中的养分不存在显著相关性。

Characteristics of needle nutrients and their retranslocation of urban common coniferous trees

Nutrient (including N, P, K, Na, Ca and Mg) concentrations and their retranslocation efficiencies in needles of some common coniferous tree species in urban Hefei were studied. The results from the study showed that there were notable differences in nutrient using efficiency and nutrient retranslocation amongst tree species. Among the nutrient measured elements, P appeared the greatest in using efficiency and retranslocation which were, respectively, 461-4 495 g/g and 5%-64% for different species, respectively. The other elements were ranked as follows, K 215-567 g/g and 13%-64% , N 62-114 g/g and 10%-40% , Na 364-424 g/g and 7%-24% , Mg 214-316 g/g and -57% -12%. Ca had the lowest use efficiency and was accumulated in the fallen needles. The regression analysis showed that there existed significant correlations between N and Na using efficiencies (p =0.012) and between P and Ca using efficiencies (p =0.004) among species. However, the nutrient using efficiency Was not significantly correlated with the corresponding soil nutrient.