Cascading effects of N fertilization activate biologically driven mechanisms promoting P availability in a semi‐arid grassland ecosystem. (4th March 2021)

• Record Type: Journal Article
• Authors: Cui, Haiying; Sun, Wei; Delgado‐Baquerizo, Manuel; Song, Wenzheng; Ma, Jian‐Ying; Wang, Keying; Ling, Xiaoli
• Editors: Veen, Ciska
• Is Part Of: Functional ecology. Volume 35:Number 4(2021)
• Page Start: 1001
• Page End: 1011
• Publication Date: 2021-03-04
• Subjects: cascading effect -- ecosystem structure and function -- enzymatic and genetic process of phosphatase -- nitrogen fertilization -- phosphorus cycle; Ecology -- Periodicals; 574.505
• DOI: 10.1111/1365-2435.13773
• Languages: English
• ISSNs: 0269-8463

Abstract

Abstract: Nitrogen (N) fertilization due to N deposition, N in manure from grazing livestock and direct input to soil by humans are impacting our terrestrial ecosystems globally. However, to date, our understanding of how artificial gradients of N fertilization indirectly affect phosphorus (P) availability by altering the rates and interrelationships of multiple structural and functional attributes of terrestrial ecosystems is still limited. Here, we conducted a 3‐year field experiment to evaluate the direct and indirect effects of multiple level of N addition on a wide range of ecosystem structural and functional attributes associated with >20 plant, soil and microbial variables in a semi‐arid grassland. We found that N fertilization can have multiple cascading effects on ecosystem structures and functions. These cascading events ultimately result in the activation of multiple biologically driven mechanisms to promote P availability (e.g. increased soil organic P mineralization, plant phosphorus resorption, enzymatic and genetic processes of phosphatase). The increasing phosphatase production and its functional gene expression, and decreasing plant and microbial biomass might imply important shifts in the carbon‐use strategies of plants and microbes allocating more resources to high‐C consuming enzymatic and genetic processes and less in plant and microbial biomass. Nitrogen addition decreases fungal community biomass which suggests the decoupling of key symbiotic plant–fungal relationships for nutrient acquirement. Overall, our study advances our understanding of how and why N fertilization simultaneously influences multiple structural and functional attributes, ultimately accelerating phosphorus cycle in terrestrial ecosystems. Abstract : A free plain Language Summary can be found within the Supporting Information of this article. 抽象的: 氮肥的使用正在显著影响全球的陆地生态系统，其中氮的来源包括：氮沉降、放牧家畜的粪肥和直接人为的土壤输入。但是，迄今为止，我们对模拟的氮肥梯度如何通过改变陆地生态系统的多种结构和功能属性的大小和相互关系而间接影响磷的可利用性的理解还十分有限。我们开展了为期三年的野外控制实验研究评估多个水平的氮添加对超过20个与植物、土壤和微生物相关的生态系统结构和功能指标的直接和间接影响。研究结果表明氮肥的使用对多种生态系统结构和功能产生级联影响。氮添加的级联效应最终激活多种生物驱动机制提高磷的可利用性，例如：提高有机磷矿化速率、植物磷的重吸收效率和激活磷酸酶相关的酶和基因过程。磷酸酶的产量和其功能基因表达的增加，而植物和微生物生物量的减少可能表明：植物和微生物碳利用策略的改变，即分配更多的碳给高能耗的酶和基因过程，减少对植物和微生物生物量的分配。此外，氮添加显著降低了真菌群落的生物量，结果表明关键的植物‐真菌共生关系发生了解耦合。总之，我们的研究加强了氮肥如何和为什么同时影响多种陆地生态系统的结构和功能属性，最终提高生态系统的磷循环的理解。 A free Plain Language Summary can be found within the Supporting Information of this article.