Increasing phosphorus availability reduces grassland soil N2O emission: Plants and microbes move from mutualism to self-reliance

IF 6 1区农林科学 Q1 AGRICULTURE, MULTIDISCIPLINARY

Agriculture, Ecosystems & Environment Pub Date : 2025-04-14 DOI:10.1016/j.agee.2025.109695

Jirui Gong , Shangpeng Zhang , Ying Li , Hans Lambers , Weiyuan Zhang , Siqi Zhang , Xuede Dong , Guisen Yang , Ruijing Wang , Chenyi Yan , Tong Wang

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引用次数: 0

Abstract

Phosphorus (P) availability directly affects grassland soil physicochemical properties and plant growth, which in turn alters microbially mediated nitrous oxide (N₂O) emission. Linking plant, soil, and microbial processes is helpful to reveal processes that affect the effects of soil P on N₂O emission. Here, we established five P-application treatments (control, with no P addition, and 1–12.5 g P m⁻² yr⁻¹ in treatments P1 to P12.5) to vary soil P availability. We investigated how the nutrient-acquisition strategies of Leymus chinensis, soil physicochemical properties, and microbial metabolic activity responded to P availability and assess effects on N₂O emission. The N₂O flux in the fertilization treatments was significantly lower than in the control but differed among the treatments. Plant biomass and root nonstructural carbohydrates increased significantly in P1 and P2.5, and plants increased root carbon allocation and recruited more microbes and greatly increased the nitrogen mineralization rate. This symbiotic plant–microbe association promoted plant water uptake, and soil drying increases the abundance of amoA functional gene, thereby promoting nitrification and reducing N₂O emission. Plants obtained more nutrients associated with an increase in the number of root tips and carboxylate exudation in P5 and P12.5. This self-reliance strategy increased nutrient competition, and the resulting substantial reduction of microbial biomass decreased the N₂O flux. However, the abundance of the narG gene and N₂O emission increased slightly in P12.5, whereas the microbial biomass was low but maintained a high carbon-use efficiency, reflecting a self-reliant microbial strategy to acclimate to their environment. Overall, P availability in grassland soils was inversely proportional to N₂O emission, and strongly determined plant–microbe interactions. Our results provide support for managing grass growth and N₂O emission in P-deficient grassland.

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增加磷的供应量可减少草地土壤中一氧化二氮的排放：植物和微生物从互助走向自立

磷(P)有效性直接影响草地土壤理化性质和植物生长，进而改变微生物介导的氧化亚氮（N2O）排放。将植物、土壤和微生物过程联系起来有助于揭示影响土壤P对N2O排放影响的过程。在这里，我们建立了5个施磷处理（对照，不加磷，1 - 12.5 g P m−2 yr−1，处理P1至P12.5）来改变土壤P的有效性。研究了羊草养分获取策略、土壤理化性质和微生物代谢活性对磷有效性的响应，并评估了其对N2O排放的影响。施肥处理的N2O通量显著低于对照，但各处理之间存在差异。P1和P2.5处理下植物生物量和根系非结构性碳水化合物显著增加，植物根系碳分配增加，微生物募集增多，氮矿化率大幅提高。这种植物-微生物共生关系促进了植物的水分吸收，土壤干燥增加了amoA功能基因的丰度，从而促进硝化作用，减少N2O排放。在P5和P12.5处理下，植株获得的养分更多，与根尖数量和羧酸盐分泌量增加有关。这种自力更生的策略增加了养分竞争，从而导致微生物生物量的大幅减少，降低了N2O通量。然而，在P12.5中，narG基因丰度和N2O排放量略有增加，而微生物生物量低，但保持了较高的碳利用效率，反映了微生物适应环境的自我依赖策略。总体而言，草地土壤磷有效性与N2O排放成反比，并强烈地决定了植物与微生物的相互作用。本研究结果为缺磷草地的草生长和N2O排放管理提供了支持。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Agriculture, Ecosystems & Environment 环境科学-环境科学

CiteScore

11.70

自引率

9.10%

发文量

392

审稿时长

26 days

期刊介绍： Agriculture, Ecosystems and Environment publishes scientific articles dealing with the interface between agroecosystems and the natural environment, specifically how agriculture influences the environment and how changes in that environment impact agroecosystems. Preference is given to papers from experimental and observational research at the field, system or landscape level, from studies that enhance our understanding of processes using data-based biophysical modelling, and papers that bridge scientific disciplines and integrate knowledge. All papers should be placed in an international or wide comparative context.