城镇生活污泥产品对国槐和银杏生长及氮磷钾含量的影响

为明确城镇生活污泥产品的土地利用效果，选取北京地区常用绿化造林树种国槐和银杏新造幼林为研究对象，以城镇生活污泥产品为试验材料，设置15、30、45、60、75 kg/株共5个污泥施用量梯度，以不施污泥为对照，采用随机区组排列方法进行污泥施用效果的对比试验，定期监测林木的生长指标、叶片的叶绿素含量以及叶片的氮（N）、磷（P）、钾（K）含量。结果表明，国槐胸径年增长值、冠幅投影面积年增长值在施入污泥后均有显著提高，当污泥施用量为45 kg/株时达到最大值；国槐叶片叶绿素含量随污泥施用量的增加而增加，在75 kg/株施用量下达到最高水平；施入污泥后国槐叶片的N、K含量变化不显著，高污泥施用量下P含量明显下降。添加不同量污泥后，银杏胸径年增长值、叶绿素含量均高于对照组，单株施用污泥75 kg时取得最大值；不同处理间银杏叶片中的N、P、K含量变化不显著。由此可见，城镇生活污泥产品的合理施用能够促进国槐、银杏的胸径、冠幅的生长以及叶片叶绿素的合成，在一定程度上延长国槐、银杏的绿期，但对两树种叶片中N、P、K元素积累的促进作用不显著。

Effects of Urban Sewage Sludge Products on the Growth and Nitrogen,Phosphorus and Potassium Contents of Sophora japonica and Ginkgo biloba

In order to clarify the land use effect of urban sewage sludge products, this experiment selected the newly planted young forests of Sophora japonica and Ginkgo biloba as the research objects, which were commonly used afforestation tree species in Beijing. There were 5 sludge application gradients of 15 , 30, 45, 60 kg/plant, and 75 kg/plant, no sludge application was control, and a random block arrangement method was used to compare the effect of sludge application. The growth indicators, leaf chlorophyll content and nitrogen (N), phosphorus (P) and potassium (K) content of the leaves were regularly measured. The results showed that the annual growth value of the diameter at breast height and the annual growth value of the projected area of the crown of S. japonica increased significantly after the sludge was applied, and reached the maximum when the sludge application rate was 45 kg/plant. The application rate increased with the increase of the application rate, reaching the highest level at the application rate of 75 kg/plant, the N and K content in the leaves of S. japonica did not change significantly after applying the sludge, and the P content was significantly reduced under the high sludge application rate. After adding different amounts of sludge, the annual increase in diameter at breast height and the chlorophyll content of G. biloba were higher than those of the control group, and reached the maximum when a single plant was fertilized at 75 kg, the N, P, and K contents in G. biloba's leaves did not change significantly among the treatments. It can be seen that the rational application of urban domestic sludge products can promote the growth of diameter at breast height, crown width and the synthesis of chlorophyll, and to a certain extend the green period of S. japonica and G. biloba, but the accumulation of N, P and K in leaves is not significant.