Search results for " DEGRADATION"
showing 10 items of 510 documents
CHEMICAL PULPING. Oxidative degradation of AOX in softwood-based kraft mill effluents from E C F bleachin g
2012
Abstract Softwood-based kraft mill bleaching effluents from the initial bleaching stages D0 and E1 (the bleaching sequence being D0E 1D 1 E2D2) were treated by the oxidative Fenton method (H20rFeS04) to decompose organic pollutants contammg adsorbable organic halogens (AOX). Experiments designed using the Taguchi method were applied to predict the process conditions that would result in a cost-effective and adequate removal of AOX. In addition to the composition and concentration of the reagents (H202 and Fe2+), the main process parameters selected were temperature and reaction time, while pH was adj usted to an approximate value of 4 (the volumetric ratio of the mixed effluents D0:E 1 was …
Plant diversity enhances the natural attenuation of polycyclic aromatic compounds (PAHs and oxygenated PAHs) in grassland soils
2019
Increasing plant species richness stimulates microbial activity in soil, which might favor biodegradation of polycyclic aromatic compounds (PACs). To explore the relationship between plant community composition and PACs in grassland soils (Fluvisols exposed to an urban atmosphere), we determined the concentrations of 29 polycyclic aromatic hydrocarbons (PAHs) and 15 oxygenated PAHs (OPAHs) in topsoils of 80 plots of a grassland biodiversity experiment. The plots included different levels of plant species richness (1, 2, 4, 8, 16, 60 species) and 1–4 plant functional groups (grasses, small herbs, tall herbs, and legumes) in a randomized block design. The concentrations (ng g−1) of ∑29PAHs an…
Soil macrofauna and organic matter in irrigated orchards under Mediterranean climate
2017
Soil fauna abundance and diversity and organic matter content are key indicators for the rate of soil degradation in Mediterranean-type ecosystems. The soil macrofauna populations were examined in three orange (Citrus sinensis) orchards and one persimmon (Diospyros kaki) orchard, with the same soil type and different management systems, to establish whether organic management benefits soil fauna and soil quality and what is the effect of flood irrigation. Vegetation cover, soil organic matter, bulk density and moisture were measured at each experimental site within the Canyoles watershed in Eastern Spain in summer of 2015. Earthworm abundance was highest at the organic orchard with flood ir…
Effects of agricultural management on surface soil properties and soil–water losses in eastern Spain
2009
Abstract In Spain, agriculture triggers soil degradation and erosion processes. New strategies have to be developed to reduce soil losses and recover or maintain soil functionality in order to achieve a sustainable agriculture. An experiment was designed to evaluate the effect of different agricultural management on soil properties and soil erosion. Five different treatments (ploughing, herbicide, control, straw mulch and chipped pruned branches) were established in “El Teularet experimental station” located in the Sierra de Enguera (Valencia, Spain). Soil sampling was conducted prior to treatment establishment, and again after 16 months, to determine soil organic matter content (OM), aggre…
Fire effects on soil aggregation: A review
2011
Abstract Fire can affect soil properties depending on a number of factors including fire severity and soil type. Aggregate stability (AS) refers to soil structure resilience in response to external mechanical forces. Many authors consider soil aggregation to be a parameter reflecting soil health, as it depends on chemical, physical and biological factors. The response of AS to forest fires is complex, since it depends on how fire has affected other related properties such as organic matter content, soil microbiology, water repellency and soil mineralogy. Opinions differ concerning the effect of fire on AS. Some authors have observed a decrease in AS in soils affected by intense wildfire or …
Spatial microbial community structure and biodiversity analysis in "extreme" hypersaline soils of a semiarid Mediterranean area
2015
In recent years specific attention has been paid on the biotechnological potential of microorganisms in extreme soils, in particular in saline soils. Salinity is one of the most widespread soil degradation processes on the Earth, and saline soils can be defined as extreme soils or border line habitats in which several factors, as high salt content, may limit the growth of organisms. In this study, the physical, chemical and microbiological soil properties were investigated in the shallower horizon of natural saltaffected soils in Sicily (Italy). The main aim of the research was to evaluate the structure and diversity of bacterial and archaeal communities by terminal-restriction fragment len…
Agriculture and grazing environments
2019
Abstract The increase in world population increases the pressure on soil resources and triggers land degradation. Agricultural and grazing environments are one of the most vulnerable ecosystems to this process. Degradation affects importantly soil fertility. Millions of hectares are affected and soil productivity is endangered. This decreases soil ability to provide ecosystem services in quantity and quality. Managers and decision-makers should be open to adopt environmentally-friendly practices and contribute to land degradation neutrality. This chapter focuses on the problems induced by some of the most common soil degradation processes caused by in agriculture and grazing activities. Rev…
Assessment of soil suitability for improvement of soil factors and agricultural management
2019
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The effects of solar radiation in archaeological sites
2013
Ruined walls, paving and decorative elements of archaeological sites are mainly composed of materials with chemical, physical and biological degradation problems that are primarily due to environmental factors. The conservation of archaeological finds requires a protection against these factors. Solar radiation may constitute one of those causes of deterioration. In recent decades the use of glass to cover archaeological sites has been more and more widespread (Fig. 1). The purpose of those glass covers is to reconcile the need of the display capabilities with the preservation of the remains. In general, a protective cover structure determines new conditions that must be carefully controlle…
Rediscovery of the enigmatic solifuges (Arachnida: Solifugae) at Lampedusa Island (Italy)
2018
Solifuges were recorded in Italy for the first time in 1956, on the island of Lampedusa (Strait of Sicily), and classified as Biton ehrenbergi Karsch, 1880 and Biton velox Simon, 1885. More than 60 years later, we carried out the first targeted investigation of these little-known animals. A survey conducted during both spring and autumn 2017 confirmed the presence of solifuges on Lampedusa Island. We identified all specimens as B. velox and not B. ehrenbergi. We concluded that B. ehrenbergi is absent from the island, on the basis of both newly collected data and a re-evaluation of the past records. Morphology and taxonomic position of the examined specimens are discussed in light of the unr…