Measurement and simulation of herbicide transport in macroporous soils

Lysimeter experiments were carried out to study pesticide transport through macroporous soils. In order to differentiate between the effects of soil structure and chemical behaviour, the leaching experiments were conducted using disturbed and undisturbed soil samples. Two herbicides with different sorption behaviours, and bromide as tracer were applied. The results were used to validate a dynamic simulation model which considers bypass flow in macropores. The simulation results show that the model is able to reproduce the soil suction within the soil as well as the spatial distribution of bromide and the herbicides. The continuity of the macropores is most important for the efficiency of bypass flow. The results indicate that cultivation practices like ploughing significantly influence the temporal and spatial distribution of the macropores. © 1998 SCI.     

Fox sightings in a city are related to certain land use classes and sociodemographics: results from a citizen science project

Background

Red foxes (Vulpes vulpes L.) have become successful inhabitants of urban areas in recent years. However, our knowledge about the occurrence, distribution and association with land uses of these urban foxes is poor, partly because many favoured habitats are on private properties and therefore hardly accessible to scientists. We assumed that citizen science, i.e. the involvement of the public, could enable researchers to bridge this information gap. We analysed 1179 fox sightings in the city of Vienna, Austria reported via citizen science projects to examine relationships between foxes and the surrounding land use classes as well as sociodemographic parameters.

Results

Conditional probabilities of encountering foxes were substantially higher in gardens, areas with a low building density, parks or squares as compared to agricultural areas, industrial areas or forests. Generalized linear model analyses showed that sociodemographic parameters such as education levels, district area, population density and average household income additionally improved the predictability of fox sightings.

Conclusions

Reports of fox sightings by citizen scientists might help to support the establishment of wildlife management in cities. Additionally, these data could be used to address public health issues in relation with red foxes as they can carry zoonoses that are also dangerous to humans.

     

Report on the 43rd Annual Meeting of the DPG-Working Group Nematology

Journal of Plant Diseases and Protection -     

Spatial patterns of soil biological and physical properties in a ridge tilled and a ploughed Luvisol

The present study was conducted to determine the spatial heterogeneity of bulk density, soil moisture, inorganic N, microbial biomass C, and microbial biomass N in the ridge tillage system of Turiel compared to conventional mouldboard ploughing on three sampling dates in May, July, and August. The soil sampling was carried out under vegetation representing the ridge in a high spatial resolution down the soil profile. Bulk density increased with depth and ranged from 1.3 g cm⁻³ at 10 cm depth to 1.6 g cm⁻³ at 35 cm in ploughed plots and from 1.0 g m⁻³ at 5 cm to 1.4 g m⁻³ at 35 cm in the ridges. In the ploughed plots, the contents of microbial biomass C and microbial biomass N remained roughly constant at 215 and 33 μg g⁻¹ soil, respectively, throughout the experimental period. The microbial biomass C/N ratio varied in a small range around 6.4. In the ridged plots, the contents of microbial biomass C and microbial biomass N were 5% and 6% higher compared to the ploughed plots. Highest microbial biomass C contents of roughly 300 μg g⁻¹ soil were always measured in the crowns in July. The lowest contents of microbial biomass C of 85–137 μg g⁻¹ soil were measured in the furrows. The ridges showed strong spatial heterogeneity in bulk density, soil water content, inorganic nitrogen and microbial biomass.     

Effects of elevated CO2, water stress, and inoculation with Glomus intraradices or Pseudomonas mendocina on lettuce dry matter and rhizosphere microbial and functional diversity under growth chamber conditions

Purpose  

In this study, we investigated the effects of elevated atmospheric CO₂, drought, and inoculation with a plant-growth-promoting rhizobacterium (PGPR) or an arbuscular mycorrhizal (AM) fungus on microbial community composition and functional diversity in the rhizosphere of Lactuca sativa L. cv. Tafalla.     

Salt-induced changes in pork myofibrillar tissue investigated by FT-IR microspectroscopy and light microscopy

FT-IR microspectroscopy and light microscopy were used to investigate pork muscle musculus semitendinosus samples, taken from three animals, that were subjected to brine salting at different concentrations (0.9, 3, 6, and 9% NaCl). Differences in spectral characteristics and in microstructure were observed in meat from animals differing in initial pH and varying salt concentrations. The FT-IR data displayed changes in the amide I region from 1700 to 1600 cm(-1). This spectral range was analyzed by principal component analysis (PCA) and partial least-squares regression (PLSR). These methods revealed correlations between the spectral data and the different animals, salt content, moisture content, pH value, and myofiber diameter. A shrinking share of alpha-helical components was related to an increase in salt concentration in the muscle. At the same time, a greater share in nonhydrogenated C=O groups (1668 cm(-1)) was related to an increase in salt concentration in the meat. The share of aggregated beta-strands differed with respect to the different animals but was not influenced by salt concentration. The meat at higher pHs (>6) had less aggregated beta-strands than that at lower pHs (5.6-5.7). It could be demonstrated that simultaneous with changes in microstructure, pH value, salt, and moisture content were alterations in the protein amide I region as measured by FT-IR microspectroscopy, revealing a relationship between these biophysical and chemical parameters and secondary protein structure attributes.     

Mitigating Negative Microbial Effects of <Emphasis Type="Italic">p</Emphasis>-Nitrophenol,Phenol, Copper and Cadmium in a Sandy Loam Soil Using Biochar

Biochars are adsorptive solids potentially of benefit to soil microbes by providing improved nutrient retention, a carbon substrate and contaminant adsorption. A 28-day incubation experiment gauged the interactive effects of biochar application and contaminants on the microbial biomass and respiration of a sandy loam soil. Soil was amended with 250 mg/kg phenol or p-nitrophenol (two toxic but nevertheless biodegradable organic contaminants) or 50 mg/kg cadmium or copper. Biochar application generally caused increased microbial respiration and biomass relative to non-amended controls. Of the heavy metal-amended soils, Cu effected significant reductions in microbial biomass carbon and basal respiration, which were improved with concurrent biochar amendment. The biochar’s functional groups are likely to have mitigated the metals’ negative effects via complexation and sorption, while the soil’s proportion of negative pH-dependent sites was increased by the pH rise induced by biochar application, allowing more cationic retention. Organic contaminant-spiked soils had higher microbial biomass-specific respiration without biochar amendment, indicating that surviving microbes utilised the compounds and necromass as substrates. Paranitrophenol proved to be particularly toxic without biochar application, causing marked reductions in the microbial quotient and biomass carbon. Remarkably, concurrent biochar and pNP application led to hugely increased microbial biomass carbon and nitrogen, significantly higher than those in contaminant-free replicates. It is likely this arose from biochar sorbing the contaminant and allowing its microbial utilisation as a carbon and nitrogen source, stimulating growth. Biochar application is a highly promising strategy for reducing the soil microbial toxicity of heavy metals and aromatic organic contaminants, particularly p-nitrophenol.     

Ecologically Based Strategies for Pest Control in Grassland Ecosystems

The researches were carried out in 2007, 2008 and 2009 at Cluj-Napoca （Romania）, in laboratory and field conditions （grassland ecosystems）, in four experiments. Our purpose was to study and use some ecological pest control methods based on indirect and direct strategies： （1） the harmful fauna monitoring in grassland ecosystems and useful fauna identification （by visual control, manually collecting, striking method on a tarpaulin）; （2） the use of some physico-mechanical and biotechnical methods （use of barriers-vessels, repellents, attractant traps-alimentary, visual） to control the pests. The researches concerning the indirect strategies, carried out from Mars 2007 to September 2009. There were identified 28 pest species and 29 useful ones. The direct strategies to control the pests consisted of 3 experiments. The use of colored traps with water （August 2008） on a meadow with ryegrass and clover, in 6 variants （white, silver, orange, green, blue and red） ＋ control （yellow）, recorded a very good efficacy at all variants excepting the red trap （variant 6）. The use of repellents （August 2008）, absinth decoction （against aphids and ants）, bracken extract （against aphids and snails）, common tansy decoction （against ants and soil pests） and kaolinite （against a large amount of pests）, recorded good results removing the pests. The attractant traps with alimentary baits （beer）, meant the use of 10 vessels on a 1000 m2 area, which captured 200 slugs （August 2009）. All three methods recorded a good efficacy against the pests.     

Can drought tolerance of Norway spruce (<Emphasis Type="Italic">Picea abies</Emphasis> (L.) <Emphasis Type="Italic">Karst</Emphasis>.) be increased through thinning?

To investigate whether drought tolerance of individual trees can be increased through the provision of more growing space, trees from a thinning experiment were analysed for reductions in radial growth during drought years and their subsequent recovery. Tree-ring widths were quantified on increment cores as well as stem discs of 32 trees from stands of a thinning trial established in 1974 in 27-year-old spruce stands in the Alpine Foreland of Southwest Germany. Three different thinning regimes of the trial were selected for this study: unthinned control (8 trees), moderate (13 trees) and heavy thinning (11 trees) intensities. All trees sampled were of a co-dominant to dominant canopy status. The standardisation of growth data was carried out using the software program ARSTAN (University of Arizona). For the year 1976—a widespread and severe drought year in Germany—we found year ring widths were not reduced compared to those of the pre-drought years for all treatments. However, we observed the formation of false year rings and resin ducts for this year in all trees investigated. The drought events in 1992 and 2003 led to severe growth depressions in the year of the drought event in all trees, regardless of previous thinning regimes. However, the resilience—the recovery of basal area growth in subsequent years—was significantly more rapid in trees from heavily thinned stands, even if the drought event occurred more than 10 years after the last thinning intervention. This indicates a shorter stress period for trees with more growing space, which may reduce the susceptibility to secondary pathogens or pest species such as bark beetles.