Seasonal drought in Mediterranean soils mainly changes microbial C and N contents whereas chronic drought mainly impairs the capacity of microbes to retain P
Marañón Jiménez, Sara (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Asensio, Dolores (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Sardans i Galobart, Jordi (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Zuccarini, Paolo (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Ogaya Inurrigarro, Romà (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Mattana, Stefania (University of Antwerp. Department of Biology)
Peñuelas, Josep (Centre de Recerca Ecològica i d'Aplicacions Forestals)

Data:	2022
Resum:	Intensification of droughts may aggravate the generally low capacity of Mediterranean soils to store C and nutrients and induce soil C:N:P stoichiometric imbalances through its impact on soil microbial biomass and activity. Soil microbes may nonetheless have different responses to seasonal and chronic drought, but very few studies investigate long-term drought periods under field conditions. This study compares the effects of seasonal drought versus the impacts of 16 years of chronic experimental drought on microbial biomass and nutrients and assess the implications for soil nutrient availability and biogeochemical functioning in a Mediterranean forest. The chronic drought treatment reduced substantially and persistently microbial biomass C, N and particularly P, probably due to P-sparing community shifts or microbial adaptations. The smaller microbial N pool and lower mineralization activity contributed to the accumulation of C- and N-rich organic compounds in the soil and to a lower availability of mineralized forms of N during the vegetation growing season. As a result, chronic drought conditions may increase the risks of N losses from the plant-soil system in Mediterranean ecosystems. Microbial C:N ratios remained unaltered under chronic drought compared to control, likely associated with the equivalent accumulation of C- and N-rich osmolytes by microbial communities. In contrast, microbial biomass increased its C content relative to N content in response to seasonal drought, but also reduced considerably its N and P pool. Therefore, while microbial P was more sensitive to chronic water stress, microbial N and C were more closely coupled to the seasonal fluctuations of water availability.
Ajuts:	Agencia Estatal de Investigación PID2019-110521GB-I00 European Commission 610028 Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-1005
Nota:	Altres ajuts: acords transformatius de la UAB
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Drought stress ; Microbial nutrients ; Microbial osmolytes ; Soil enzymes ; Soil nutrients ; Water limitation
Publicat a:	Soil biology and biochemistry, Vol. 165 (February 2022) , art. 108515, ISSN 0038-0717

DOI: 10.1016/j.soilbio.2021.108515

11 p, 1.4 MB

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