Search results for "Microbial bioma"
showing 5 items of 35 documents
Microbial biomass carbon dynamics in a long-term tillage and crop rotation experiment under semiarid Mediterranean conditions
2015
Microbial biomass carbon (MBC) of soil is an important ecological indicator of nutrient cycling and soil fertility. In addition, it responds to the changes of soil fertility more rapidly than soil organic matter. The aim of the present work was to evaluate the effect of a long-term implementation of a conservative soil management strategy (No Tillage [NT]) compared to the inversion tillage (conventional tillage [CT]) on the soil MBC in a range of crops - continuous durum wheat (WW), wheat after fababean (FW) and faba bean after wheat (WF). MBC of NT plots was higher than CT. In addition, the content of MBC varied with sampling time during the growing season; this variation did not show a co…
Dynamique de la communauté microbienne de sols tropicaux suite à une application répétée de fertilisants organiques et minéraux
2019
Organic waste products (OWP) with NPK mineral fertilization are known to have an impact on soil microbial communities. However, dynamic of these communities following a repeated OWP and NPK application has not been well described. In the present study, this dynamic was observed on soil sampled at the La Mare (La Réunion) field experiment, which was set up in 2013. This experiment includes control plot (without organic input, but mineral fertilization) and several plots receiving different types of OWP coupled with NPK fertilization. Physico-chemical parameters were measured on soils and OWPs (2013 to 2017). Soil microbial biomass (from 2013 to 2018) and the structure of microbial community …
Response of microbial biomass and carbon dynamics to changing hydrological conditions in old peat deposits
2018
Peatlands play key roles in the global ecosystem carbon (C) balance, as important C-stores. Their efficiency as long-term C-stores or atmospheric C sink is affected by the rate of microbial mineralization. Most studies on the climate change effects on the microbial communities and C-cycling in peatlands have focused on the surface layers. This thesis compared microbial biomass, community composition and internal C cycling processes in drained vs. natural peat profiles with focus on deep old peat. Using the phospholipid fatty acid (PLFA) and rRNA gene analyses, the study particularly looked at the impact of long-term drainage and the short-term effects of temperature and water content on the…
Effets du mode de travail du sol sur les microorganismes à l'échelle du profil cultural
2009
Soil tillage modifies the location of crop residues and soil structure and affects microbial populations and activities such as mineralization of soil organic matter. The aim of this work was to compare the effect of two tillage systems (traditional mouldboard ploughing, LT, and reduced tillage, TR) on crop residues distribution and soil structure as well as their consequences on soil microbial biomass (BM), the potential activity of C mineralization (Cmin) and soil bacterial community structure (through T-RFLP). In order to study simultaneously the effects of soil structure modifications and crop residues distribution on these microbial parameters we used a stratified sampling scheme based…
Dynamics of soil organic matter pools after agricultural abandonment
2014
Changes of land use from croplands to natural vegetation usually increase Carbon (C) stocks in soil. However, the contribution of old and new C to various pools still is not clearly analyzed.We measured the 13C signature of soil organic carbon (SOC) pools after vegetation change from vineyard (C3) to grassland (C4) under Mediterranean climate to assess the changes of old and new C in total SOC, microbial biomass (MB), dissolved organic C (DOC), and CO2 efflux from soil. Development of the perennial grass Hyparrhenia hirta (C4) on vineyard abandoned for 15 or 35 years ago increased C stocks for 13% and 16%, respectively (in the upper 15 cm). This increase was linked to the incorporation of n…