城市排水污泥对竹柳扦插苗生理特性及N、P、K含量的影响

Effects of urban sewage sludge application on physiological characteristics and nitrogen,phosphorus and potassium contents of Salix spp.cuttings

为探究施用城市排水污泥对竹柳扦插苗生理特性的影响,在平原沙地苗圃环境下,设置3、6、9 kg·m^(-2)共3个污泥施用量梯度,分别设为T1、T2、T3处理,以不施污泥为对照(CK),测定各处理扦插苗的成活率,定期监测叶片叶绿素、可溶性蛋白、非结构性碳水化合物(NSC)含量的动态变化,并在生长季末测定各器官全氮(N)、全磷(P)、全钾(K)含量.结果表明:随着污泥施用量的增加,叶绿素含量总体呈现先增加后减少的趋势,扦插35、50、65 d后,T1处理的叶绿素含量均达到最大值,且与CK的差异显著;可溶性蛋白含量总体表现为先增加后减少再增加的趋势,T1处理在整个测试期间始终处于最高水平;T1、T2、T3处理对NSC的积累均存在明显的促进作用;施入污泥后,N、P、K在根的分配率和含量均高于CK,T1处理显著提高了茎及全株的K含量,各处理间的全株N、P含量均差别不大.综合考虑施入污泥后竹柳扦插苗各生理指标的响应情况以及本研究中的污泥施用量,认为3 kg·m^(-2)为较适宜的施用量.

To provide reference for the application of urban sewage sludge on Salix spp.cultivation,3 dosages of sludge,3(T1),6(T2)and 9 kg·m^(-2)(T3)and the control were set up in sandy nursery soil.Survival rates of the propagated Salix cuttings were determined on 35 d,and the dynamic changes on contents of leaf chlorophyll,soluble protein,and non-structural carbohydrates(NSC)were monitored.Total nitrogen(N),phosphorus(P),and potassium(K)contents of different organs were measured at the end of the growing season.The results showed that chlorophyll content of Salix cuttings tended to increase and then decrease as the sludge dosage increased.T1 led to the highest chlorophyll contents compared with other groups,which were significantly different from the control.Soluble protein content witnessed similar variation trend as the chlorophyll content,plateaued on 50 d,and then went down in all treatments except slight uptick in T2 on 80 d.Soluble protein content was highest in T1 numerically throughout the growing season.T1,T2 and T3 all significantly enhanced NSC accumulation in leaves.Sludge application also improved the distribution rates and contents of N,P and K in roots compared with the control.K allocation in the stem and total K content of the entire cutting were significantly elevated in T1,while total N and P contents were not different among the treatments.To summarize,application of urban sewage sludge at the rate of 3 kg·m^(-2) was recommended for Salix cultivation considering the overall physiological responses to sludge.