摘要
磷是陆地生态系统植物生长的限制性元素之一,氮沉降会通过调控土壤磷循环过程改变磷素活性和生物有效性,但目前关于氮沉降下草地土壤磷组分变化及其影响因素的认识依然有限。本研究以黄土丘陵区草地为对象,基于野外3年不同水平氮添加试验,测定土壤磷组分、土壤理化性质、土壤微生物生物量和磷转化酶活性,旨在揭示氮添加对草地土壤磷组分的影响及其调控途径。结果表明:土壤中、高活性磷含量随着氮添加浓度增加显著增加,稳定态磷含量随着氮添加浓度增加显著下降;氮添加导致有机磷含量显著增加了1.71%~5.14%,但无机磷含量显著下降。氮添加降低了土壤pH,高浓度氮添加促进了土壤碳、氮、磷的积累,并使土壤微生物生物量碳、氮、磷含量分别增加了18.11%、38.27%、41.73%;随氮添加水平增加,土壤碱性磷酸单酯酶、磷酸二酯酶和植酸酶活性均先降低后升高。土壤养分、pH、微生物生物量和酶活性对土壤磷组分变化的解释率为68.64%;结构方程模型分析结果表明,氮添加引起了土壤微生物代谢底物养分的变化,进而对微生物生物量和磷转化胞外酶活性产生显著影响,并通过这两个途径共同调控土壤磷组分。
Phosphorus is one of the limiting nutrients for plant growth in terrestrial ecosystems.Nitrogen deposition can change the activity and bioavailability of phosphorus by regulating soil phosphorus cycle.However,the under-standing of changes in soil phosphorus fractions and their influencing factors under nitrogen deposition is still limit-ed.To reveal the effects of nitrogen addition on soil phosphorus fractions and its regulation pathways,we measured soil phosphorus fractions,soil physicochemical properties,soil microbial biomass,and phosphorus invertase activity in a three-year field experiment with different nitrogen addition levels in a loess hilly region.The results showed that the contents of moderately and highly labile phosphorus increased significantly with increasing nitrogen addition lev-els,while the contents of non-labile phosphorus decreased significantly.Organic phosphorus content significantly in-creased by 1.71%-5.14%,but inorganic phosphorus content significantly decreased.Nitrogen addition reduced soil pH.High nitrogen addition level promoted the accumulation of soil C,N,and P,and increased soil microbial bio-mass C,N,and P by 18.11%,38.27%,and 41.73%,respectively.With increasing nitrogen addition levels,the activities of soil alkaline phosphatase,phosphodiesterase and phytase decreased first and then increased.Soil nutri-ents,pH,microbial biomass,and enzyme activities explained 68.64%of the variation of soil phosphorus fractions.Structural equation model analysis showed that nitrogen addition induced changes in soil microbial metabolizing sub-strate nutrients,which had significant effects on microbial biomass and the activities of phosphorus conversion extra-cellular enzymes,and co-regulated soil phosphorus fractions through these two pathways.
作者
卢笑玥
朱运
李江文
邓健
徐莉萍
吴林豪
张丹
LU Xiaoyue;ZHU Yun;LI Jiangwen;DENG Jian;XU Liping;WU Linhao;ZHANG Dan(College of Life Sciences,Yan'an University,Yan'an 716000,Shaanxi,China)
出处
《生态学杂志》
CAS
CSCD
北大核心
2024年第8期2472-2479,共8页
Chinese Journal of Ecology
基金
国家自然科学基金项目(41907086)
延安大学校级科研计划项目(YDY2020-33)
国家级大学生创新创业训练计划项目(202210719020)资助。
关键词
氮沉降
磷组分
微生物
磷酸酶活性
黄土丘陵区
nitrogen deposition
phosphorus fraction
microorganism
phosphatase activity
loess hilly region
作者简介
卢笑玥,女,1998年生,硕士研究生,主要研究方向为生态恢复及其环境效应。E-mail:yylxy413@163.com。;通信作者:邓健,E-mail:deng050702@126.com。
