Search results for "ORGANIC MATTER"
showing 10 items of 577 documents
Effect of earthworms on decomposition processes in raw humus forest soil: A microcosm study
1990
The earthworms Lumbricus rubellus (Hoffmeister) and Dendrobaena octaedra (Savigny) were studied in the laboratory to determine their effects on decomposition and nutrient cycling in coniferous forest soil. CO2 evolution was monitored, and pH, PO 4 3− −P, NH 4 + −N, NO 3 − −N, total N, and total C in the leaching waters were measured. After three destructive samplings, numbers of animals, mass loss, pH, and KCl-extractable nutrients were analysed. The earthworms clearly enhanced the mass loss of the substrate, especially that of litter. L. rubellus stimulated microbial respiration by 15–18%, whereas D. octaedra stimulated it only slightly. The worms significantly raised the pH of the leachin…
Relationships between Suspended and Sediment Organic Matter in a Semi-Enclosed Marine System: The Stagnone Di Marsala Sound (Western Sicily)
1997
To gather information on the interactions between the sediment and suspended organic matter pools in the Stagnone di Marsala, water and sediment samples were collected, on a monthly basis, at 11 stations. Water temperature and salinity showed a clear seasonality whilst particulate and sediment organic matter did not show any clear seasonal pattern. Relative abundances of suspended and sediment organic matter, on the other hand, appeared to be site-dependent and controlled mainly by the dynamic balance between resuspension and sedimentation. High quantities of both suspended and sediment total organic matter were present, while very low algal biomasses (in terms of chlorophyll-a concentratio…
Photoautotrophic community changes in Lagunillo del Tejo (Spain) in response to lake level fluctuation: Two centuries of sedimentary pigment records
2009
Lagunillo del Tejo is a small doline lake in a karstic region of the Iberian Ranges (central-eastern Spain) that undergoes significant lake level fluctuation in response to changing aquifer influxes. In order to assess changes in the primary producer community in the lake over the last two centuries and to elucidate whether these were conditioned by climatic variability, photosynthetic pigments and their derivatives were extracted from the sediments and the data analysed using multivariate statistical techniques. Quantitative variations in total pigment concentrations through the sedimentary sequence are considered a result of changes in sedimentation rate, largely due to lake level fluctua…
Soil solarization with biodegradabile materials and its impact on soil microbial communities.
2008
Soil solarization (SS) seems one of the most promising techniques to control soilborne pathogens, but an important limitation to the diffusion of this technique is due to the drawback regarding the disposal of the used plastic materials. A possible solution to this problem is the use of biodegradable plastics. The aim of this study was compare the impact of SS with biodegradable materials with SS with plastic film and others pest management techniques (i.e. organic matter amendment, calcium cyanamide and Dazomet fungicide application) on crop productivity, soilborne disease incidence, weed suppression, and soil chemical (total N, ammonium, nitrate, available phosphorus, organic matter, hydr…
DYNAMICS OF SOIL NUTRIENT STATUS OF HIGHBUSH BLUEBERRY IN LATVIA, 2006-2017
2019
In Latvia, the first commercial highbush blueberry (Vaccinium corymbosum L.) plantings have been established on a few hectares at the end of the 1990th. Since then, a remarkable growth has noticed and today the total cultivated area reaches 280 hectares. An increasing market demand for fresh and processed berries provides a future upward trend in the development of blueberry crop in Latvia. In general, blueberry is a highly specialized crop that has definite soil agrochemical and climatic requirements. There are two main soil types used for blueberry cultivation in Latvia: well-drained acid sandy soils with high organic matter content and sphagnum peat soils. Evaluation and management of pl…
Properties and structure of raised bog peat humic acids
2013
Abstract Humic substances form most of the organic components of soil, peat and natural waters, and their structure and properties differ very much depending on their source. The aims of this study are to characterize humic acids (HAs) from raised bog peat, to evaluate the homogeneity of peat HAs within peat profiles, and to study peat humification impact on properties of HAs. A major impact on the structure of peat HAs have lignin-free raised bog biota (dominantly represented by bryophytes of different origin). On diagenesis scale, peat HAs have an intermediate position between the living organic matter and coal organic matter, and their structure is formed in a process in which more labil…
Effects of Pentachlorophenol and Biotic Interactions on Soil Fauna and Decomposition in Humus Soil
1995
In a laboratory experiment, effects of chemical stress (pentachlorophenol, PCP, at concentrations of 0, 50, and 500 mg/kg) and biotic interactions (nematodes in the presence or absence of collembolas and enchytraeids) on the community structure of soil animals and decomposition processes were studied. PCP was strongly adsorbed to humus that contained 65% organic matter. Numbers of fungal-feeding nematodes decreased significantly at the highest PCP concentration, while no effects were found in bacterial feeders. There were differences in the numbers of nematodes between different animal combinations, but at the highest PCP concentration, collembolas and enchytraeids had no effect on them. Nu…
Contamination from polycyclic aromatic hydrocarbons (PAHs) in the soil of a botanic garden localized next to a former manufacturing gas plant in Pale…
2010
The Botanical Garden lies within the city of Palermo, a few meters away from one of the largest unused Manufacturing Gas Plant in Sicily. The total concentrations of PAHs (23 compounds) in the soil of Botanical Garden ranged from 947 to 18,072 microg/kg. The wide range of PAH concentrations (RSD=84%) found in the soil samples indicates heterogeneous levels of contamination in the area and this can be explained by considering the different tree distributions which prevents the homogeneous deposition of pollutants on the soil. Soils collected in the Botanical Garden generally showed the highest PAH concentrations, being almost 2-3 times higher than the concentration samples obtained in the ur…
Water-stable aggregates and organic matter pools in a calcareous vineyard soil under four soil-surface management systems
2006
. Vineyards in Champagne, France are generally situated on slopes where the soils are subject to erosion. Therefore it is important to find a soil-surface management practice that protects the soil against water erosion. We assessed the potential of mulches or grass covers to stabilize soil aggregates in a calcareous sandy loam from a vineyard in Champagne after 9 years under different management systems. Four different treatments were studied: (i) a bluegrass (Poa pratensis) surface cover between the vine rows (GC) with bare soil under the vines (R); two organic mulches of (ii) coniferous (CB) or (iii) poplar (PB) bark that covered the entire soil surface, and (iv) bare soil between the ro…
Heavy metals in sewage sludges contribute to their adverse effects on the arbuscular mycorrhizal fungusGlomus mosseae
2003
Applying sewage sludges to agricultural land is a widespread practice because of the sludges’ agronomic value as a source of plant nutrients and organic matter. Nevertheless, sludges often contain micropollutants that can constitute a menace for health and the environment. Arbuscular mycorrhizal fungi are sensitive to sewage sludges that have been spiked, or not, with metallic trace elements (MTE). Here we have investigated if MTE in sewage sludges could be responsible for effects on mycorrhizal development betweenGlomus mosseae andMedicago truncatula. The impact of a dehydrated or composted urban sewage sludge spiked or not with MTE, was tested on spore germination and root colonization by…