Search results for "Microbial biomass C"
showing 8 items of 8 documents
Dynamics of soil organic carbon pools after agricultural abandonment
2014
Abandonment of agricultural land and the subsequent recolonization by natural vegetation is known to cause increases in C contents, contributing to reduction in atmospheric CO2 concentrations. Assessment of the possible mitigation of CO2 excess requires understanding the SOC dynamics, the origin of C pools and the pathways of their transformation. The aims of this work were to assess, by using the δ13C signature, the changes of old and new organic C in total (soil organic carbon, SOC) and labile (microbial biomass C, MBC, dissolved organic C, DOC, CO2 efflux from soil) pools after vegetation change from vineyard (C3) to grassland (C4) under semiarid Mediterranean climate. Colonization of ab…
Long‐Term Tillage and Cropping System Effects on Chemical and Biochemical Characteristics of Soil Organic Matter in a Mediterranean Semiarid Environm…
2015
Several studies have reported how tillage and cropping systems affect quantity, quality, and distribution of soil organic matter (SOM) along the profile. However, the effect of soil management on the chemical structure of SOM and on its hydrophobic and hydrophilic components has been little investigated. In this work, the long-term (19 years) effects of two cropping systems (wheat monoculture and wheat/faba bean rotation) and three tillage managements (conventional, reduced, and no tillage) on some chemical characteristics of SOM and their relationships with labile carbon (C) pools were evaluated. Soil samples were taken from the topsoil (0–15 cm) of a Chromic Haploxerert (central Sicily, I…
Soil microbial biomass carbon and fatty acid composition of earthworm Lumbricus rubellus after exposure to engineered nanoparticles
2014
none 6 no First Online: 14 October 2014 The aim of this work was to investigate the effect of engineered nanoparticles (NPs) on soil microbial biomass C (MBC) and on earthworm Lumbricus rubellus. An artificial soil was incubated for 4 weeks with earthworms fed with vegetable residues contaminated by NPs, consisting of Ag, Co, Ni and TiO2. After the treatments, soils were analysed for MBC and total and water soluble metal-NPs, whereas earthworms were purged for 28 days and then analysed for fatty acids (FAs) and total metal-NPs. Longitudinal sections of earthworms were investigated by environmental scanning electron microscopy (ESEM), equipped with energy-dispersive X-ray spectroscopy (EDS),…
SOIL QUALITY INDICATORS AS AFFECTED BY SHALLOW TILLAGE IN A VINEYARD GROWN IN A SEMIARID MEDITERRANEAN ENVIRONMENT
2016
Within the Mediterranean basin, soil tillage enhances the mineralisation of soil organic matter. We assessed the short-term impact of shallow tillage [field cultivator (FC), rotary tiller (RT) and spading machine (SM)] on some soil quality indicators [bulk density, water-stable aggregates, total and labile organic C pools (microbial biomass and extractable organic C), soil respiration and related eco-physiological indexes] in a Sicilian vineyard. Also no tillage was included. We hypothesized that (i) RT and FC worsened soil quality indicators more than SM, and (ii) within the same tillage system, labile C pools, soil respiration and eco-physiological indexes will respond more efficiently th…
Native and planted forest species determine different carbon and nitrogen pools in Arenosol developed on Holocene deposits from a costal Mediterranea…
2016
In a coastal Mediterranean area, the effects of two native [Quercus ilex (Holm), Alnus glutinosa and Fraxinus oxycarpa (Hygro)] and one planted [Pinus pinaster (Pine)] forest species on both content and quality of organic C and total N pools in Arenosols was assessed. Three soil profiles per each forest cover were opened and sampled. Total N in the organic layers was not affected by forest covers, whereas total organic C ranged from 36.1 to 63.2 Mg ha−1, being organic layers under Hygro those with the highest contents. Total organic C in the first 50 cm of mineral soil was 64 Mg ha−1 under Holm and 36.7 and 37.6 Mg ha−1 under Pine and Hygro, respectively. Soil covered by Holm and Hygro stor…
Effects of compost input and tillage intensity on soil microbial biomass and activity under Mediterranean conditions
2010
Organic amendment and tillage reduction are two common practices to contrast soil organic matter decline, thus promoting sustainable cropping and carbon sequestration. In a horticultural land use system under Mediterranean climate, we evaluated the 9-year effects of two compost inputs (15 and 30 t ha−1 y−1, low and high input, respectively) and two tillage intensities (intensive and reduced) on soil macronutrients concentration, microbial biomass and activity. Total organic C, total N and POlsen were smaller in plots amended at low input, whilst intensive tillage decreased them at both compost inputs. These decreases in intensively tilled plots was ascribed to the disruption of soil aggrega…
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…
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…