黔西北土法炼锌废渣堆场修复植物叶片和废渣的生态化学计量特征

为探讨土法炼锌废渣堆场实现生态修复后废渣-植物系统中植物内稳性以及不同植被类型与氮磷限制的关系，选择黔西北威宁县猴场镇已开展生态修复达4年的土法炼锌废渣堆场为研究区域，以废渣堆场上生长良好的5种优势乔灌草植物即构树（Broussonetia papyrifera）、柳杉（Cryptomeria fortunei）、大叶醉鱼草（Buddleja davidii）、芦竹（Arundo donax）、三叶草（Trifolium repens L）为研究对象，研究5种优势植物在铅锌废渣堆场中碳（C）、氮（N）、磷（P）、钾（K）的生态化学计量特征及其相互关系。结果表明：不同优势植物修复的废渣中C、N含量较高，P、K含量较低，三叶草废渣中N、P含量显著高于其他植物（p<0.05），有效氮、有效磷与速效钾表现为三叶草废渣较高，柳杉较低；各元素化学计量特征表现为C∶P > C∶K > C∶N > N∶P > N∶K > P∶K，三叶草废渣中N∶K、P∶K显著高于其余四种植物。5种植物叶片中N含量整体较低，草本植物三叶草N、P、K含量明显高于其余几种植物；通过叶片N∶P分析表明，除三叶草生长受P限制，其余4种植物生长都受N限制。废渣与植物叶片中养分含量间的相关性表明，植物叶片中N、P、K含量分别与废渣中有效态养分（N、P、K）含量呈显著正相关（p<0.05）。除叶片N∶P与废渣中有效态养分（N、P、K）含量呈正相关外，叶片中其余元素间的化学计量比均与废渣中有效态养分（N、P、K）含量呈负相关，其中叶片C∶K、P∶K与废渣中有效态养分（N、P、K）含量呈极显著负相关（p<0.01）。因此，废渣中N、P、K的有效性显著影响着植物叶片中N、P、K的含量及生态化学计量特征。

Ecological Stoichiometric Characteristics of Plant Leaves and Slag at a Restoration Site of Indigenous Zinc Smelting Slag in Northwestern Guizhou

The study aimed to investigate the plant internal stability and the relationship between vegetation type and restriction of nitrogen and phosphorus in the waste slag-plant system of revegetated zinc smelting waste slag yards, a zinc smelting waste slag yard, which had been revegetated plants for 4 years in Monkey Town, Weining County, northwestern Guizhou, was selected as the study area, and five dominant plants (Broussonetia papyrifera, Cryptomeria fortunei, Buddleja davidii, Arundo donax, Trifolium repens L), which grew well at the waste slag yard, were selected as the study objects. The eco-stoichiometric characteristics of carbon (C), nitrogen (N), phosphorus (P) and potassium (K) in these five dominant plants at the zinc smelting waste slag yard were studied. The results showed that contents of C and N in waste residues repaired by different dominant plants were relatively higher, while contents of P and K were relatively lower. The contents of N and P were significantly higher in slags restored by Trifolium repens L than by other plants (p<0.05). The available contents of N, P and K were higher in slags restored by Trifolium repens L, and lower in slags restored by Broussonetia papyrifera. The stoichiometric characteristics of elements were C:P > C:K > C:N > N:P > N:K > P:K. The N:K and P:K ratios were significantly higher in slags restored by Trifolium repens L than by other four plants. The N content was lower overall. The contents of N, P and K were significantly higher in Trifolium repens L than in other plants. The N:P ratio in leaves indicated that the plant growth was restricted by N except Trifolium repens Lwhich was restricted by P. The correlations among nutrients in waste slags and in plant leaves indicated that contents of N, P and K in leaves significantly and positively correlated with their availabilities in slags (p<0.05), and that, except the ratio of N:P in leaves which was positively correlated with the available contents of nutrient (N, P, and K), stoichiometric ratios of nutrient elements in leaves were negatively correlated with the available contents of nutrients (N, P and K), specially ratios of C:K and P:K in leaves which were negatively correlated with the available contents of nutrients (N, P, and K) very significantly (p<0.01). Therefore, we concluded that contents of nutrients (N, P and K) and their ecological stoichiometry in plant leaves were affected significantly by available contents of nutrients in waste slags of the study site.