Search results for "Soil"
showing 10 items of 3493 documents
Soil decomposer community as a model system in studying the effects of habitat fragmentation and habitat corridors
2008
Abstract Due to the practical difficulties of experimental study of habitat fragmentation and habitat corridors at the landscape scale, the use of smaller-scale model systems has been offered as a feasible alternative to uncover the ecological phenomena taking place in fragmented environments. In this mini-review, we consider the applicability of the soil decomposer community as such a model system. For the most part, this article is based on the few studies that have explicitly addressed this question by experimental manipulations of the natural habitat of soil decomposer community. However, to broaden the view, we also capitalize upon studies focusing on the effects of isolation and soil …
The asexual enchytraeid worm Cognettia sphagnetorum (Oligochaeta) has increased Cu resistance in polluted soil
2001
We studied Cu resistance in the asexual (reproduction through fragmentation) enchytraeid worms (Cognettia sphagnetorum, Oligochaeta) originating from two sites: one uncontaminated, and another contaminated by heavy metals. Adult worms were smaller and population density was lower at the polluted site. However, adults from the contaminated site had better survival in Cu-contaminated soil, but lower survival as juveniles (fragments). As we do not know the genetic basis of Cu resistance of the worms, it may have been reached by acclimatization via induced Cu regulation. Because fragmentation is the only mode of reproduction, all phenotypic properties (including resistance) of a parental genera…
Litter quality, land-use history, and nitrogen deposition effects on topsoil conditions across European temperate deciduous forests
2019
Topsoil conditions in temperate forests are influenced by several soil-forming factors, such as canopy composition (e.g. through litter quality), land-use history, atmospheric deposition, and the parent material. Many studies have evaluated the effects of single factors on physicochemical topsoil conditions, but few have assessed the simultaneous effects of multiple drivers. Here, we evaluate the combined effects of litter quality, land-use history (past land cover as well as past forest management), and atmospheric deposition on several physicochemical topsoil conditions of European temperate deciduous forest soils: bulk density, proportion of exchangeable base cations, carbon/nitrogen-rat…
Spatiotemporal patterns in methane flux and gas transfer velocity at low wind speeds: Implications for upscaling studies on small lakes
2016
Lakes contribute significantly to the global natural emissions of methane (CH4) and carbon dioxide. However, to accurately incorporate them into the continental carbon balance more detailed surveys of lacustrine greenhouse gas emissions are needed, especially in respect to spatiotemporal variability and to how this affects the upscaling of results. We investigated CH4 flux from a small, wind-shielded lake during 10 field trips over a 14 month period. We show that floating chambers may be used to calibrate the relationship between gas transfer velocity (k) and wind speed at 10 m height (U10) to the local system, in order to obtain more accurate estimates of diffusive CH4 flux than by applyin…
Spatial variability of soil roughness in persimmon plantations: A new combined ISUM (improved stock unearthing method) approach
2019
Made available in DSpace on 2019-10-06T16:49:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-11-01 Universidade Estadual Paulista Soil roughness (SR) is an ecological indicator that describes the distribution of soil surface accumulations and ponds in a terrain, which allows understanding the connectivity of the flows as they act as sinks and sources of water and sediments. There is a set of methods that allows investigating the SR, and we test the use of the improved stock unearthing method (ISUM) as an easy-to-apply and low-cost approach. The ISUM has been initially tested in vineyards using the graft union and measures in the inter-row areas to assess the current soil surface l…
Colonization of adventitious roots ofMedicago truncatulabyPseudomonas fluorescensC7R12 as affected by arbuscular mycorrhiza
2008
Pseudomonas fluorescens C7R12 was previously shown to promote colonization of Medicago truncatula roots by Glomus mosseae BEG12. To gain more insight into the interaction between C7R12 and BEG12, the cell organization of C7R12 was characterized on adventitious roots mycorrhized or not with BEG12 and on extraradical hyphae. Bacterial cell observations were made using the immuno-fluorescence technique and confocal laser scanning microscopy. Five types of cell organization, so-called organization types (OT), were identified: small or large single cells, cells by pair and cells in microcolonies or in strings. The frequencies of each OT on the roots were expressed as the percentage of observatio…
Switching from conventional tillage to no-tillage: Soil N availability, N uptake,15N fertilizer recovery, and grain yield of durum wheat
2018
Abstract This 2-year study, performed in a typical Mediterranean environment on three soil types (two Inceptisols and one Vertisol), aimed to improve understanding of the factors that play a major role in determining crop response when soil management shifts from conventional tillage (CT) to no-tillage (NT). The effects of NT on the soil nitrogen (N) availability, N uptake, 15N fertilizer recovery, and grain yield of durum wheat were evaluated in comparison to CT under five different N fertilization rates (0, 40, 80, 120, and 160 kg N ha−1). Compared to CT, NT negatively affected grain yield in one of the two years but only in the two Inceptisols. On average, a considerable grain yield adva…
Living in isolation for almost 40 years: molecular divergence of the 28S rDNA and COI sequences between French and Polish populations of the cave bee…
2021
The paper gives the results of the first studies on the molecular divergence between native and non-native populations of Speonomus normandi hydrophilus (Jeannel, 1907). This species is endemic to Massif Arize in the Central Pyrenees (France), and represents highly specialised organisms that live underground. In 1982, one hundred specimens of S. normandi hydrophilus had been experimentally introduced into the Dzwonnica Cave (Poland). Since then, a numerous population has developed in the Towarna-Dzwonnica cave system, and the neighbouring Cabanowa Cave. After almost 40 years of isolation between native and non-native populations, the genetic variations were examined using the COI and 28S rD…
Insecticide residues in cotton soils of Burkina Faso and effects of insecticides on fluctuating asymmetry in honey bees (Apis mellifera Linnaeus).
2011
8 pages; International audience; Four insecticides (acetamiprid, cypermethrin, endosulfan and profenofos) are used quarterly in the cotton-growing areas of Burkina Faso, West Africa. These insecticides were investigated in soils collected from traditionally cultivated and new cotton areas. Also, the effects of insecticide exposure on the developmental instability of honey bees, Apis mellifera, were explored. In soil samples collected three months after insecticide treatments, endosulfan and profenofos concentrations varied in the range of 10-30μgkg(-1) in the traditionally cultivated zones and 10-80μgkg(-1) in the new cotton zones, indicating a pollution of agricultural lands. However, only…
Integrated management strategies of Meloidogyne incognita and Pseudopyrenochaeta lycopersici on tomato using a Bacillus firmus-based product and two …
2019
Abstract Because of the restrictions on chemical pesticide use and their negative effects on the environment, as well as on human and animal health, alternative strategies for plant pest and pathogen managements are highly desirable. The objective of this work was to evaluate the suitability of a commercial formulation of Bacillus firmus strain 1-1582, applied either alone or in combination with oxamyl or fosthiazate, to control the southern root-knot nematode Meloidogyne incognita and the fungal plant pathogen Pseudopyrenochaeta lycopersici under greenhouse conditions during two tomato crop cycles. Application of B. firmus suppressed nematode population levels during the second crop cycle …