Search results for "forest"
showing 10 items of 3780 documents
Contents of free amino acids in needles of Norway Spruce trees in relation to novel forest decline. Studies on trees from a site in the northern Blac…
1993
The free amino acid content in needles of Norway spruce trees (about 45-year-old) was determined by means of HPLC. The studied trees have been growing at a forestry site in the Black Forest which is characterized by a high impact of ozone and magnesium deficiency. Measurements were carried out on visibly healthy and on damaged trees on several dates during two vegetation periods and during the course of a day. The amino acids occurring at the highest concentrations were glutamate, arginine, aspartate, and glutamine. The typical seasonal changes in the content of free amino acids, with their minimum during summer, were disturbed in the needles of the damaged trees. Particularly in summer and…
The effect of iron on the biodegradation of natural dissolved organic matter
2016
Iron (Fe) may alter the biodegradation of dissolved organic matter (DOM), by interacting with (DOM), phosphorus (P) and microbes. We isolated DOM and a bacterial community from boreal lake water and examined bacterial growth on DOM in laboratory experiments. Fe was introduced either together with DOM (DOM-Fe) or into bacterial suspension, which led to the formation of insoluble Fe-precipitates on bacterial surfaces (Fe coating). In the latter case, the density of planktonic bacteria was an order of magnitude lower than that in the corresponding treatment without introduced Fe. The association of Fe with DOM decreased bacterial growth, respiration, and growth efficiency compared with DOM alo…
Soil water repellency assessment in olive groves in Southern and Eastern Spain
2016
Soil water repellency (SWR) has been reported under different soils, land uses and regions of the world, particularly in forest land and after wildfires, yet the understanding of this variable in agricultural lands is still rather limited. This study presents the characterization from field-based measurements of SWR in four contrasted olive groves (Olea europaea L.) in Spain in terms of different environmental conditions and management: abandoned and commercial farms under permanent cover crop, conventional tillage and herbicide use. The main objectives were [1] to evaluate the potential occurrence, intensity and persistence of soil water repellency in different types of olive groves and [2…
Silicatein: from chemical through enzymatic silica formation, to synthesis of biomimetic nanomaterials
2012
Silicateins are the enzymes that had been identified in sponges, then sequenced and expressed. They are not only the enzymes facilitating biosilica synthesis but also function as structure-guiding and structure-forming proteins. The three minireviews highlight the principles of silicatein-mediated biosilica formation and outline the bionic strategies which might be used for the design and fabrication of novel materials.
Direct acid-catalysed mechanical depolymerisation of fibre sludge to reducing sugars using planetary milling
2016
Abstract This study performed a direct solvent-free acid-catalysed mechanical depolymerisation of fibre sludge to reducing sugars which involves one step of acid milling in a planetary mill. The common reported ‘solvent-free’ mechanocatalytic depolymerisation of lignocellulose which includes 1) acid impregnation, 2) vacuum evaporation and 3) mechanocatalytic depolymerisation was also performed as a reference. The major converted monosaccharides were determined by capillary electrophoresis and the results of total reducing sugar (TRS) yields were carried out based on the 3,5-dinitrosalicylic acid (DNS) method. The results showed that the TRS conversion of direct acid-catalysed mechanical dep…
Variability of near-surface saturated hydraulic conductivity for the clay soils of a small Sicilian basin
2019
Abstract Proper characterization of saturated hydraulic conductivity, Ks, of clay soils in a hillslope or a basin is still a challenge for soil science. In this investigation, the clay soils of the Maganoce (Sicily, Italy) basin were sampled at 19 sampling sites by the BEST procedure of soil hydraulic characterization. More OM implied less compact conditions (decreasing dry soil bulk density; coefficient of determination, R2 = 0.67), more stability to water of the soil aggregates (increasing water stable aggregates; R2 = 0.83) and, consequently, higher Ks values (R2 = 0.54). Variability of Ks was lower in the steeper zones of the basin than in the flatter ones. A comparison with the Ks data…
The effect of soil on human health: an overview
2018
Soil has a considerable effect on human health, whether those effects are positive or negative, direct or indirect. Soil is an important source of nutrients in our food supply and medicines such as antibiotics. However, nutrient imbalances and the presence of human pathogens in the soil biological community can cause negative effects on health. There are also many locations where various elements or chemical compounds are found in soil at toxic levels, because of either natural conditions or anthropogenic activities. The soil of urban environments has received increased attention in the last few years, and they too pose a number of human health questions and challenges. Concepts such as soi…
Effects of soil fauna on leaching of nitrogen and phosphorus from experimental systems simulating coniferous forest floor
1990
Long-term experiments (97–98 weeks) were carried out in macrocosm systems simulating the complexity of coniferous forest soil. The macrocosms were partially sterilized by freezing, thawing and drying, then re-inoculated with microbes alone or microbes + soil fauna. Removable microcosms containing birch litter, spruce litter, or humus were inserted into the substrate humus in the macrocosms. Two experiments used organic matter only, and in the third there was mineral soil below the humus. The macrocosms were incubated in climate chambers that simulated both summer and winter conditions. At 4- to 6-week intervals the substrates were irrigated for analyses of pH, total N, NH 4 + −N, NO 3 − −N,…
Evaluation of the soil fauna impact on decomposition in a simulated coniferous forest soil
1990
Long-term experiments (ca. 2 years) were carried out in laboratory systems that simulated the complexity of a coniferous forest floor. The test materials were partially sterilized by freezing and thawing, and reinoculated with (1) microbes alone or (2) microbes with fauna. Removable microcosms containing birch litter, spruce litter, or humus were inserted into a humus substrate. Two experiments used organic matter only, and another included a layer of mineral soil below the humus. Both were incubated in climate chambers that simulated both summer and winter conditions. The evolution of CO2 was measured at regular intervals. In order to determine the C content of the leachates, the macrocosm…
Changes in soil redox potential in response to flood irrigation with waste water in central Mexico
2017
Irrigation with untreated sewage water adds fresh organic matter to the soil. When it is applied by flooding, as in the Mezquital Valley of Mexico, many of the pores in the soil become temporarily waterlogged and depleted of oxygen, and reduction generates nitrous oxide (N2O) and methane (CH4). We monitored the redox potential, Eh, in the soil at two sites in the Mezquital Valley to discover whether the short-term gaseous emissions matched the changes in Eh. One site is irrigated periodically by flooding with waste water and has alfalfa, rye grass and maize grown in succession; the other site grows maize with water from summer rain only. Each electrode buried in the soil for the purpose pro…