Doctoral thesis (Dissertations and theses)
Assessing microbial diversity changes associated with different tillage and crop residue managements: study case in a loamy soil
Degrune, Florine
2017
 

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Keywords :
Agriculture; Soil tillage; Crop residue management; Microbial diversity; Metagenomics; 454-pyrosequencing; Bacteria; Fungi
Abstract :
[en] The major challenge of modern agriculture is to produce enough food for the growing population, and at the same time, minimize environmental harm. To meet this challenge, Agroecology aims to replace non-renewable external inputs with ecological processes to diversify the ecosystem services and attenuate the dis-services of agriculture. In this light, the ability to manage the soil microbiota, that has great effects on soil quality, is receiving attention. Plowing, the most widely used tillage practice in intensive agriculture has proven its efficiency in maximizing crop productivity, but its long term detrimental effects on soil quality, such as soil erosion and organic matter loss, have called for alternative tillage practices. However, the success of the implementation of these practices in Europe is still debated. In the upper part of Wallonia (Belgium), the soil is highly fertile and 80% of land is occupied mostly by intensive cropping systems. To date in Walloon cropping systems, few studies have explored the soil microbiota in association with different soil managements. Here, we used a meta-barcoding approach to explore differences in soil microbial community structure under two contrasting tillage regimes, conventional (CT) and reduced tillage (RT), either with or without crop residue retention. The effects of these soil treatments were explored at different depths and during the growing season of two crops. Our work demonstrated clear differences in microbial diversity between tillage regimes, but no clear differences between residue management practices. The observed differences appeared to be associated with differences in physical (e.g. structure and moisture) and chemical (nutrients) soil properties. Notably, the nutrient concentrations and moisture were higher under CT than under RT. Overall, soil under CT had higher or similar microbial diversity than under RT. Analysis of β-diversity revealed differences in the taxonomic structure of microbial communities. Certain microbial groups were more abundant under CT than under RT and vice versa. For example, mycorrhizal fungi, economically and ecologically important in agroecosystems, were more abundant under RT. Finally, the magnitude of tillage effects on the microbial diversity varied strongly with the sampling depth, whereas it varied moderately with the growing season. This work highlighted CT was not necessarily unfavourable in maintaining microbial diversity when compared to RT. However, the study raises new questions regarding the impacts of microbial diversity changes on soil functioning. We encourage researchers to undertake further investigations into the functional role of microbiota in order to improve our understanding of agroecosystem functioning and its sustainability.
Disciplines :
Agriculture & agronomy
Author, co-author :
Degrune, Florine ;  Université de Liège > Agronomie, Bio-ingénierie et Chimie (AgroBioChem) > Microbiologie et génomique
Language :
English
Title :
Assessing microbial diversity changes associated with different tillage and crop residue managements: study case in a loamy soil
Alternative titles :
[fr] Evaluation de la diversité microbienne associée à différents travaux du sol et gestions des residus: cas d'étude en sol limoneux
Defense date :
16 March 2017
Number of pages :
166
Institution :
ULiège - Université de Liège
Degree :
Docteur en sciences agronomiques et ingénierie biologique
Promotor :
Vandenbol, Micheline ;  Université de Liège - ULiège > Département GxABT > Microbial, food and biobased technologies
President :
Fauconnier, Marie-Laure  ;  Université de Liège - ULiège > Département GxABT
Jury member :
Bodson, Bernard ;  Université de Liège - ULiège > Département GxABT
Cornelis, Jean-Thomas ;  Université de Liège - ULiège > Département GxABT > Echanges Eau - Sol - Plantes
Ongena, Marc ;  Université de Liège - ULiège > Département GxABT > Microbial, food and biobased technologies
Hartmann, Martin
Roisin, Christian
Commentary :
AgricultureIsLife
Available on ORBi :
since 10 March 2017

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