Search

Because of the use of agricultural land for wine production and the frequent use of copper (Cu)-based fungicides, Cu concentration has been increasing in soils in many parts of the world. In vineyards with acid parent materials, low soil pH may also encourage Cu toxicity, but it is common to use lime in order to increase the soil pH and improve crop yields. Thus, vineyard soils may have large variations in pH, which will affect the microbial communities, making it difficult to isolate possible toxic effects of Cu on soil microbes. Here, analyses of phospholipid fatty acid (PLFA) patterns and pollution-induced community tolerance (PICT, using leucine incorporation) were used to study the effect of Cu accumulation at small to medium concentrations in acid soils (pH 4.05.8) in vineyards with different land-use history (young, old and abandoned vineyards). The results suggested that soil pH played a dominant role in determining the composition of the microbial community of the soils. Only a small effect of soil Cu could be detected and the effect on microbial community composition was much less than the pH effect. PICT analysis suggested that bacterial communities in old vineyards were more tolerant of Cu than those in the abandoned vineyards. However, increased PICT (Cu tolerance of the bacterial community) was not directly correlated with Cu concentration in the soils. Instead, the estimated Cu tolerance was significantly correlated with soil pH. (Less)

The immediate effect of low and high severity wildfires on the main soil properties, as well as their short‐ and medium‐term evolution under field conditions, was examined. The study was performed with three pine forest soils (two Leptosols and one Humic Cambisol, developed over granite and basic schist, respectively), located in the Atlantic humid temperate zone (Galicia, NW Spain). Samples were collected from the A‐horizon (0–5 cm depth) of the burnt and the corresponding unburnt soils, immediately and 3, 6 and 12 months after the wildfires. Most properties analysed exhibit immediate fire‐induced changes and different evolution depending on fire severity and soil type. In general, immediately after the fire pH and soil properties related to nutrients availability increased and cation exchange capacity decreased, whereas properties related to soil organic matter content (C, N, Fe and Al oxides) had a variable effect depending mainly on the soil studied; all these modifications were accentuated by fire severity. These effects were attenuated in the short term in the soil affected by a low severity wildfire, but they lasted for at least 1 year in the soils affected by high severity wildfires, particularly in the Leptosols. The results showed the importance of the fire as a disturbance agent in the dynamic of nutrients and soil organic matter that is directly related with soil quality in the Galician forest ecosystems., This study was supported by the Consellería de Educación y Ordenación Universitaria de la Xunta de Galicia and by the Comisión Interministerial de Ciencia y Tecnología (CICYT), Spain.

To detect effects of Cu pollution, the Cu tolerance of soil bacterial communities extracted from several vineyards located in NW Spain was measured. Bacterial community tolerance was estimated by means of the thymidine (TdR) and leucine (Leu) incorporation techniques using either IC(50) values (the log of the metal concentration that reduced incorporation to 50%) or the percentage of activity at one specific Cu concentration (10(-6) mol L(-1)). The tolerance measurements by the TdR incorporation technique were similar to those obtained by the Leu incorporation method, indicating that the two methods were equivalent in terms of suitability for detecting the toxicity of Cu to soil bacterial communities. The two tolerance indices considered (IC50 values and percentage of activity) were closely correlated (r = 0.975, P < 0.001), showing that both were equally good in measuring Cu tolerance of the bacterial community. An increased bacterial community tolerance to Cu, indicating a pollution effect, was observed in vineyard soils with more than 100 mg Cu kg(-1) soil. Thus, the long-term use of Cu in vineyards has a toxic effect on the soil bacterial community, resulting in an increased tolerance. An effect of increased levels of Cu could not be detected when measuring bacterial community activity, pointing to the increased sensitivity to detect toxicity in field studies using tolerance measurements.

Co-composting of barley waste with liquid poultry manure was assessed by monitoring several chemical and biological parameters related to compost stability/maturity throughout a 103 day period. A compost of solid poultry manure was used as the control, because a compost could not be obtained from the liquid manure. The materials composted reached thermophilic stage temperatures within 4 days, lasting for more than 10 days; thereafter the temperature decreased rapidly to around ambient levels. The initial pH value was around 9 for both mixtures and, despite an initial decrease, high values were maintained over the entire co-composting process. Electrical conductivity increased with composting time, while the opposite behaviour was observed for total carbon content. Organic matter loss in the co-composting of barley waste with liquid poultry manure was 35%. In general, the final products showed physicochemical characteristics considered normal for such materials, but pH and ammonia content values were high. The results of a bioassay test performed with seeds of three plant species (ryegrass, wheat and barley) indicated that the co-compost could be considered mature from a biological point of view, since phytotoxicity was absent for ryegrass and barley. Comparison of these data with those obtained for solid poultry manure indicated that barley waste notably improved the composting efficiency as well as the quality of the final product. © 2003 Society of Chemical Industry

Dynamic parameters of the transformation of chestnut burr/leaf litter with solid poultry manure (ratio 1:3) into a fertiliser using a co-composting process are reported in this work. Determinations of temperature, granulometric composition, pH, electrical conductivity, organic matter content, nitrogen content and available potassium and phosphorus as well as biological germination tests on ryegrass (Lolium perenne), barley (Hordeum vulgare) and wheat (Triticum aestivum) seeds were performed. The loss of organic matter was only 6.27% (w/w dry weight) and the available potassium changed from 2820 to 3265 mg kg−1 in the co-compost studied. Germination tests showed that the co-compost was mature in 103 days. © 2001 Society of Chemical Industry