北方城市10种常见树木凋落叶的分解及养分释放特征

将城市绿化树木凋落叶用作施肥材料直接还田或制备生物质有机肥是实现凋落叶资源化利用的有效途径。采用尼龙网袋法对10种城市绿化树木凋落叶的分解及其养分释放特征进行研究。结果表明:1）N含量以构树凋落叶较高（40.37 mg/g），P含量以七叶树、构树、樱花和鹅掌楸凋落叶较高（12.92～23.03 mg/g），K含量以构树和紫叶李凋落叶较高（5.88～6.38 mg/g）；Zn含量以樱花和紫叶李凋落叶较高（18.53～19.95 μg/g）；Mn含量以紫叶李凋落叶较高（65.24 μg/g）；木质素含量以栾树、银杏、青桐和七叶树凋落叶较高（30.18～34.60 mg/g）。2）10个树种中，构树、火炬树和紫叶李的凋落叶分解较快（T为1.02~1.08 a），栾树、鹅掌楸、樱花、海棠、七叶树和青桐次之（T为1.12～1.18 a），银杏凋落叶分解较慢（T为1.22 a）。3）凋落叶分解过程中N元素释放较快的为构树、樱花和火炬树凋落叶，青桐凋落叶表现出“富集”的现象；P元素释放较快的为海棠、火炬树、鹅掌楸、构树和樱花凋落叶；对于K元素，除了七叶树和银杏凋落叶释放稍慢（T为1.26～1.43 a），其他凋落叶释放均较快（T为1.00～1.05 a）。4）相关性检验表明，凋落叶中含有较高的N、P含量有利于凋落叶分解，而凋落叶中含有较高的木质素含量及较大的木质素/N值，则不利于凋落叶的分解。因此，构树凋落叶适宜于制备N肥、P肥和K肥；七叶树、樱花和鹅掌楸凋落叶适宜于制备P肥；紫叶李凋落叶适宜于制备K肥。根据不同凋落叶的养分含量和分解释放特征可以有选择性和针对性地应用于农田施肥或制备生物质有机肥。

Decomposition and Nutrient Release Characteristics of Ten Common Tree Leaves in Northern Cities

Using litter leaves of urban greening trees as fertilizing materials to directly return to the field or preparing biomass organic fertilizers is an effective way to realize the utilization of litter leaves.Litter bag method was used to study the decomposition and nutrient release characteristics of ten species of urban greening trees,i.e.,Firmiana simplex,Ginkgo biloba,Prunus cerasifera,Koelreteria paniculata,Aesculus chinensis,Cerasus serrulata,Rhus typhina,Malus spectabilis,Broussonetia papyrifera,and Liriodendron chinense.The results shows that 1) the N content was higher in the leaves of B.papyrifera (40.37 mg/g); the P content was higher in A.chinensis,B.papyrifera,C.serrulata and L.chinense (12.92-23.03 mg/g); the K content was higher in B.papyrifera and P.cerasifera (5.88-6.38 mg/g); the Zn content was higher in C.serrulata and P.cerasifera (18.53-19.95 μg/g); the Mn content was higher in P.cerasifera (65.24 μg/g).The lignin content was higher in K.paniculata,G.biloba,F.simplex and A.chinensis (30.18-34.60 mg/g).2) Among the ten tree species,litter leaves of B.papyrifera,R.typhina and P.cerasifera decomposed quickly with the turnover period (T) values ranging from 1.02-1.08 a),followed by K.paniculata,L.chinense,C.serrulata,A.chinensis and F.simplex (T:1.12-1.18 a),the fallen leaves of G.biloba decomposed slowly (T:1.22 a).3) During the decomposition,the tree species elements that could quickly release N faster were the leaves were B.papyrifera,C.serrulata and R.typhina.The leaves of F.simplex showed an “enrichment” phenomena.Trees species that could quickly release P were M.spectabilis,R.typhina,L.chinense,B.papyrifera and C.serrulata; For element K,except for A.chinensis and G.biloba,from which the release process was slightly slower (T:1.26-1.43 a),other species could release K quickly (T:1.00-1.05 a).4) Correlation test showed that the higher N and P contents in the fallen leaves was beneficial to the decomposition,while the higher lignin content and high lignin/N ratio was not conducive to the decomposition.Therefore,the litter leaves of B.papyrifera is suitable for preparing nitrogen fertilizer,phosphate and potash fertilizer; the litter leaves of A.chinensis,C.serrulata and L.chinense are suitable for preparing phosphate fertilizer; Prunus cerasifera is suitable for preparing potash fertilizer.According to the nutrient content and decomposition and release characteristics of different tree species,it can be selectively and specifically apply to farmland fertilization or the preparation for biomass organic fertilizer.