森林土壤氧化亚氮排放对磷添加响应的研究进展

Progress in Studies of Responses to Phosphorus Addition of Soil Nitrous Oxide Emissions from Forest Soil

氧化亚氮(N_(2)O)是大气中的主要温室气体之一,其浓度上升会加剧全球变暖。森林土壤在调解大气N_(2)O浓度中发挥着至关重要的作用,近年来,为了提高森林生产力,磷(P)肥使用量逐年增加;然而,与氮沉降或氮添加对森林土壤N_(2)O排放的影响相比,人们对P添加如何影响森林土壤N_(2)O排放的认识还十分有限。本研究综述森林土壤N_(2)O排放对P添加的响应及其作用机制。由于植物和土壤微生物(微生物量、群落组成和微生物活性)对P添加的响应存在差异,致使森林土壤N_(2)O排放对P添加的响应呈促进、抑制和无影响3种结果。总体而言,P添加可缓解植物和土壤微生物的P限制,土壤N_(2)O排放对P添加的响应受土壤初始养分(N、P)状态调控。P添加能够促进植物根系对无机氮的吸收和/或提高微生物固氮,从而降低森林土壤N_(2)O排放;P添加还能刺激硝化和反硝化细菌的活性,增加森林土壤N_(2)O排放。此外,P添加也可能通过缓解土壤酸化,影响丛枝菌根真菌共生和凋落物分解,实现对土壤N_(2)O排放的调控。在今后的森林管理中,可以考虑将P添加作为温室气体减排的一种策略。

Rising nitrous oxide(N_(2)O)concentrations in the atmosphere have exacerbated global warming.Forest soil plays an important role in regulating atmospheric N_(2)O concentration.Recently,application of phosphate(P)fertilizer was increased for improving forest productivity.However,compared with the well-known effects of nitrogen(N)deposition or N addition on N_(2)O emission from forest soil,how the P addition affects the N_(2)O emission from forest soil is still limited and lacks in-depth understanding.This study presents a review of the responses and mechanism of N_(2)O emissions from forest soils to P addition.Due to the different responses of plant and soil microorganisms(microbial biomass,community composition and microbial activity)to P addition,phosphorus addition can increase,reduce or not change the N_(2)O emission from forest soil.Overall,phosphorus addition alleviated the P-limitation of plants and soil microbes.The effect of P addition on soil N_(2)O emissions was governed by the initial status of soil nutrients(N,P).P addition can promote the absorption of inorganic N by plant roots and/or microbial N immobilization,thus reducing the N_(2)O emission from forest soil,it can also stimulate the activity of nitrification and denitrification bacteria,subsequently promote the N_(2)O emission from forest soil.Furthermore,phosphorus addition may also regulate soil N_(2)O emissions by alleviating soil acidification,affecting arbuscular mycorrhizal fungi symbiosis and litter decomposition,which requires further studies.In the future forest management,the addition of phosphorus can be considered as a strategy for reduction of greenhouse gas emission.