Soil bacteria respond to regional edapho-climatic conditions while soil fungi respond to management intensity in grasslands along a European transect

A Barreiro,A Fox,M Jongen,J Melo,M Musyoki,A Vieira,J Zimmermann,G Carlsson,C Cruz,A Lüscher,F Rasche,L Silva,F Widmer,L.M Dimitrova Mårtensson

doi:10.1016/j.apsoil.2021.104264

Abstract

Soil microbial community structure is determined by environmental conditions and influenced by other factors, such as the intensity of the land use management. Studies addressing the effect of environmental factors and management on grassland soil microbial communities at the continental scale are missing, and the wide range of ecosystem services provided by these ecosystems are thus also wanting. To address this knowledge gap, this study presents data on grassland soil microbial communities along a pan-European agro-ecological gradient. The transect included five geographical locations (Sweden, Germany, Switzerland, Portugal mainland, Portugal Azores). At each location, soils were collected in two regions characterized by favourable and less favourable conditions for plant growth. In each of these ten regions, grasslands along a gradient of management intensity were selected, i.e. grassland under intensive, less intensive and extensive management. Phospholipid fatty acid analysis (PLFA) was used to characterize the microbial community structure (PLFA pattern) in relation to climatic and soil properties. Over the whole geographical range, the environmental properties determined the soil microbial community structure. In Sweden and Switzerland, the regional growth conditions had the strongest influence on the soil microbial communities, while in Germany, Portugal mainland and Azores the management intensity was more important. Splitting up this whole community response into individual groups reveals that, in general, saprotrophic fungal biomarkers were highest in extensively managed grasslands while bacterial biomarkers differed mainly between the regions. We conclude that at the transect level, climate and soil properties were the most important factors influencing soil bacterial community structure, while soil fungal groups were more responsive to grassland management intensity. Overall agricultural sustainability could benefit from informed soil health promoting management practices, and this study contributes to such knowledge, showing the importance of management for the soil microbial biomass and community structure.

Highlights

Grasslands are among the world's largest biomes which, together with other grass-dominated habitats, cover about 30–40% of the Earth's terrestrial surface (Blair et al, 2014), with 316 million ha on the European continent
The within-country nested PERMANOVA exhibited an effect of growth conditions on the Phospholipid fatty acid analysis (PLFA) pattern in SE (p < 0.001) and CH (p < 0.01), but not in the other countries (p > 0.05) (Table 2)
The countrywise nested PERMANOVA indicated an effect of management in tensity on the PLFA pattern in all countries (p < 0.001 for SE, CH, Portugal mainland (PT), AZ and p < 0.05 for DE) (Table 2)

Summary

Introduction

Grasslands are among the world's largest biomes which, together with other grass-dominated habitats (e.g., savannah, shrubland and tundra), cover about 30–40% of the Earth's terrestrial surface (Blair et al, 2014), with 316 million ha on the European continent (area from MODIS, FAOSTAT, 2015). Continuous expansion of agricul tural land, climate change, grazing and other management strategies are important issues that affect the survival of semi-natural grasslands across Europe (Veen et al, 2009), and these threatening processes are expected to continue during the decades (Millennium Ecosystem Assessment, 2005). Grassland ecosystems can be described by their age and continuity such as annual, cultivated, permanent, temporary, naturalized, seminatural and natural grasslands (Allen et al, 2011). All, excluding the natural one, can be defined as anthropogenic grasslands, as they are maintained by diverse management strategies, from extensive grazing and annual cutting to intensive farming practices associated with intensive grazing, frequent cutting, ploughing, sowing and/or fertiliza tion (Yuan et al, 2016). In addition to providing forage for livestock or biomass, grasslands provide various cultural, regulating and sup porting ecosystem services, e.g., landscape aesthetics, belowground carbon (C) sequestration, primary production, regulation of biogeo chemical cycles and biodiversity conservation (Lemaire et al, 2011; Pommier et al, 2017)

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Conclusion