摘要
土壤养分提升对喀斯特石漠化生态恢复可持续性至关重要,探究喀斯特凋落物分解和养分释放特征可为筛选提升土壤养分有效性的优良树种提供数据支撑。以北热带喀斯特季节性雨林广西棋子豆(Archidendron guangxiensis)、东京桐(Deutzianthus tonkinensis)、蚬木(Excentrodendron tonkinense)和海南椴(Hainania trichosperma)4种岩溶适生树种为研究对象,开展为期365d的凋落叶分解实验,分析不同树种凋落叶的分解速率和碳、氮释放特征及调控因素。结果显示:凋落叶分解速率为海南椴(k=0.66)>蚬木(k=0.45)>东京桐(k=0.42)>广西棋子豆(k=0.39),分解95%的时间分别为4.51a、6.72a、7.17a、7.68a。初始碳含量、单宁含量、比叶面积和标准持水力是共同调控质量损失率的主要化学和物理性状。碳释放速率为海南椴>东京桐>蚬木>广西棋子豆,碳释放常数k为0.74-1.17,高于全球平均值0.69。氮释放速率为海南椴>广西棋子豆>东京桐>蚬木。碳、氮释放解耦,碳释放受初始化学性状(纤维素、氮/磷、氮、碳)和物理性状(比叶面积、标准持水力)共同调控,而氮释放主要受初始化学性状(碳/氮、木质素/氮、氮、木质素、氮/磷)调控。综上,海南椴凋落叶分解及碳、氮释放速率最快,固氮树种广西棋子豆凋落叶氮含量最高且具有较高的氮释放速率。海南椴和广西棋子豆是北热带喀斯特的优势适生树种,凋落叶年输入量较大,分解速率和氮释放速率较高,可作为石漠化土壤养分提升的潜在优选树种。
Soil nutrient improvement in karst ecosystem is very important for the sustainability of ecological restoration.Exploring the characteristics of leaf litter decomposition rate and nutrient release in the karst ecosystem is of great significance to select excellent tree species that improve soil nutrient availability.Leaf litter from four native tree species(i.e.Archidendron guangxiensis,Deutzianthus tonkinensis,Excentrodendron tonkinense,and Hainania trichosperma)in a north tropical karst seasonal rainforest was collected to conduct a 365-day field decomposition experiment.Then,the litter decomposition rate and the release of carbon(C)and nitrogen(N)were investigated,and their relationships with initial physicochemical traits(i.e.C content,N content,phosphorus(P)content,cellulose content,lignin content,tannin content,C/N,C/P,N/P,lignin/N,specific leaf area,and standard water-holding capacity)were also examined.The results showed that the order of leaf litter decomposition rate was H.trichosperma(k=0.66)>E.tonkinense(k=0.45)>D.tonkinensis(k=0.42)>A.guangxiensis(k=0.39),and their times required to decompose 95%were 4.51,6.72,7.17,and 7.68 years,respectively.Initial C content,specific leaf area,standard water-holding capacity,and tannin content were the important physicochemical traits affecting leaf litter decomposition in the north tropical karst forest.The order of leaf litter C release rate was H.trichosperma>D.tonkinensis>E.tonkinense>A.guangxiensis.The constant k of C release rate ranged from 0.74 to 1.17,which was higher than the global average of 0.69.The order of leaf litter N release rate was H.trichosperma>A.guangxiensis>D.tonkinensis>E.tonkinense.The C and N release of litter were decoupled.The C release rate was controlled by both the initial chemical(cellulose,N/P,N,and C)and physical traits(specific leaf area,standard water-holding capacity)of leaf litter,while the N release rate was only controlled by the initial chemical traits(C/N,cellulose/N,N,lignin,and N/P).Taken together,H.trichosperma leaf litter has the fastest decomposition rate and the release rate of C and N,while the N-fixing tree species A.guangxiensis leaf litter has the highest N content and high N release rate.As the dominant native tree species in the karst area,H.trichosperma and A.guangxiensis have high litter fall production and high decomposition rate or N release rate,which can be used as potential tree species for improving soil nutrients in rocky desertification.
作者
裴广廷
张雪冰
贺同鑫
巢林
胡宝清
龙继凤
刘晟源
孙建飞
PEI Guangting;ZHANG Xuebing;HE Tongxin;CHAO Lin;HU Baoqing;LONG Jifeng;LIU Shengyuan;SUN Jianfei(Key Laboratory of Environment Change and Resources Use in Beibu Gulf,Ministry of Education,Guangxi Key Laboratory of Earth Surface Processes and Intelligent Simulation,Nanning Normal University,Nanning 530001,China;Nonggang Karst Ecosystem Observation and Research Station of Guangxi,Chongzuo 532499,China;Administration Center of Guangxi Nonggang National Nature Reserve,Longzhou 532400,China)
出处
《生态学报》
北大核心
2025年第15期7564-7575,共12页
Acta Ecologica Sinica
基金
广西自然科学基金项目(2021GXNSFBA220028)
国家自然科学基金项目(42277468,42467033)。
关键词
喀斯特季节性雨林
凋落物分解
养分释放
碳氮耦合
偏最小二乘回归
karst seasonal rainforest
litter decomposition
nutrient release
coupling of carbon and nitrogen
partial least squares regression
