A study of the effect of the interaction between site-specific conditions, residue cover and weed control on water storage during fallow     

Romina Fernandez  Alberto Quiroga  Elke Noellemeyer  Daniel Funaro  Jorgelina Montoya  Bernd Hitzmann  Norman Peinemann 《Agricultural Water Management》2008,95(9):1028-1040

In the semiarid central region of Argentina the probability that rainfall meets crop requirements during growing season is less than 10%, therefore fallowing has been the most important practice to assure water availability during the growing season. Various site-specific and management factors have been identified as crucial for defining fallow efficiency (FE) and final available water contents (AW). The objective of the present study was to improve our knowledge about the interactions between residue cover, weed control, soil profile depth and water storage capacity (WSC) on FE. In 10 sites covering the environments of calcareous plains and sandy plains of the semiarid central region of Argentina and with different WSC, experiments with 3 different levels of residue cover (H, M, L) and with and without weed control (C and W respectively) during fallow were set up. A completely randomized block design with four repetitions and splits plots to consider weed control was used. Soil texture and organic matter were determined in samples of the A horizon (0.20 m). Bulk density, field capacity, permanent wilting point and soil water contents (monthly frequency) were measured at depth intervals of 0.20 m to the depth of the calcite layer or to 2.00 m depth. Soil temperature was taken in weekly intervals at 0.05 m depth and weed plants, separated by species, were counted at the end of fallow in 4 repetitions of 0.25 m² in each treatment. An empirical model was developed to predict final AW under these experimental conditions. Model parameters were: Residue level, weed control, WSC, profile depth, and rainfall during fallow. Site-specific conditions (WSC and profile depth) affected water storage during fallow; soils with highest values for both parameters showed highest final AW. Weed density was the most important factor that controlled AW, with on average 35 mm less AW in W than in C treatments. Residue level had a positive effect on final AW in both C and W treatments, with a difference of 18.5 mm between H and L. An interaction between residue level and weed density was observed, indicating weed suppression in H treatments. This was also confirmed by correspondence analysis between residue level and weed species which revealed that different species were related to each level. High residue levels also decreased soil temperature, thus affecting germination of post-fallow crops. The empirical model had an overall average prediction error of 13.7% and the regression between measured and predicted values showed a determination coefficient of 0.77.  相似文献   

RNA-based disease control as a complementary measure to fight Fusarium fungi through silencing of the azole target <Emphasis Type="Italic">Cytochrome P450 Lanosterol C-14 α-Demethylase</Emphasis>     

Aline Koch  Elke Stein  Karl-Heinz Kogel 《European journal of plant pathology / European Foundation for Plant Pathology》2018,152(4):1003-1010

RNA-based disease control has shown great potential for controlling pest and diseases in crop plants. While delivery of inhibitory noncoding double-stranded (ds)RNA by transgenic expression is a promising concept, it requires the generation of transgenic crop plants, which may cause substantial delay for application strategies depending on the transformability and genetic stability of the crop plant species. Focusing on agronomic important barley - Fusarium spec. pathosystems, we have sought for alternative strategies to apply dsRNAs for fungal control. Recently, we have demonstrated that a spray application of a long noncoding dsRNA termed CYP3RNA, which targets the three fungal Cytochrome P450 lanosterol C-14α-demethylase genes FgCYP51A, FgCYP51B, and FgCYP51C, inhibits Fusarium graminearum (Fg) on barley leaves (Koch et al., PLoS Pathogens, 12, e1005901, 2016). Here we show that another Fusarium species, F. culmorum (Fc), also is sensitive to CYP51-derived dsRNAs. Treating Fc with various dsRNAs targeting the genes FcCYP51A, FcCYP51B and FcCYP51C was destructive to the fungus and resulted in growth retardation in in vitro cultures. We discuss important consequences of this finding on future RNA-based disease control strategies. Given the ease of design, high specificity, and applicability to diverse pathogens, the use of target-specific dsRNA as an anti-fungal agent offers unprecedented potential for novel plant protection strategies.  相似文献   

Hydrochars derived from sewage sludge: effects of pre-treatment with water on char properties,phytotoxicity and chemical structure     

Marc Breulmann  Elke Schulz  Manfred van Afferden  Roland A. Müller  Christoph Fühner 《Archives of Agronomy and Soil Science》2018,64(6):860-872

Large amounts of labile compounds are adsorbed to the surface of chars produced by hydrothermal carbonization (HTC). The aim of this study was to characterize the core and adsorbed fractions of hydrochars and to gain knowledge about the possibility to remove phytotoxic compounds by washings with water. Chars were produced by HTC of sewage sludge at different temperatures (180 – 200 °C) and over different periods of time (4 – 8 h). For comparison one pyrolysis char produced by thermocatalytic low temperature conversion (LTC) at 400 °C for 1 h was included in the study. The chars and their feedstocks were treated varying the duration (1 x 15, 1 × 30 and 1 × 60 min) and number (2 x 60 and 3 × 60 min) of washings. Physicochemical properties, including the molecular structure of the test materials, and their effects on germination and plant growth were analysed. Element concentrations and phytotoxic effects were reduced and the number of washings had a stronger effect than their length of time. Intensive washings with water reduced the hydrochars’ portion of biodegradable compounds significantly. However, also plant available nutrients were lost by washing with water, decreasing the value of hydrochars as a soil amendment.  相似文献   

Influence of graded EDTA applications on mobilization and translocation of trace elements—a soil column experiment          下载免费PDF全文

Elke Bloem  Iris Vogler 《植物养料与土壤学杂志》2018,181(2):220-230

Increasing concerns about potential environmental effects of ethylenediaminetetraacetic acid (EDTA) accumulation in soils require better understanding of its behavior and its effect on trace element mobilization. In this study we investigated the effect of EDTA on soil trace element mobilization in undisturbed soil columns taken from a heavy metal contaminated field. The columns were leached by EDTA solutions of different concentrations under unsaturated, steady‐state conditions. The transport of trace elements (Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sn, Zn) and EDTA was monitored by regularly collecting the leachates. After the termination of the leaching experiment the soil columns were divided into 5 layers to determine trace elements and EDTA concentrations in the soil. The results revealed that the soil analysis alone was not suitable to infer mobilization or immobilization patterns in relation to the EDTA concentration, as the mobilized fraction was too small in relation to the total trace metal concentrations in the soil. Analysis of the leachates displayed that after 2–4 pore volumes the EDTA output concentration reached about 80% of the input concentration. The trace element concentrations in the leachates showed that some elements were mobilized by EDTA (Cd, Cu, Fe, Pb, Co, Ni, Zn) while others were immobilized (Mn, Cr, Mo, Sn) in the soil columns after EDTA application.  相似文献   

Rheological properties and bread making performance of commercial wholegrain oat flours     

Edith K. Hüttner  Fabio Dal Bello  Elke K. Arendt 《Journal of Cereal Science》2010

Three commercial wholegrain oat (WO) flours from Finland (WOF), Ireland (WOI) and Sweden (WOS) were evaluated for their bread making ability with the objective of finding predictive relationships between flour physicochemical properties and bread quality. Overall, significant differences were found in the bread making properties of the WO flours. Good bread quality was obtained when using WOS and WOI flour since breads showed high specific loaf volume and slice height as well as low density and hardness. Low quality breads were obtained when WOF flour was used. In addition, positive effects on oat bread quality were observed for low batter viscosity and high deformability, as obtained for WOS and WOI. Based on the physicochemical analysis of the flours, water hydration capacity was found to be the main reason for increased elasticity of WOF batters. Small flour particle size, damaged starch granules and high protein content were identified as the key factors causing increased water hydration capacity. These findings suggest that WO flours with coarse particle size, limited starch damage and low protein content result in superior oat bread quality.  相似文献   

Development of maternal antibodies after oral vaccination of young female wild boar against classical swine fever   总被引：3，自引：0，他引：3  

Kaden V  Lange E 《Veterinary microbiology》2004,103(1-2):115-119

An experimental study was performed to investigate the development of maternal antibodies after oral immunisation of young female wild boar against classical swine fever (CSF) using C-strain vaccine. Our results demonstrated that maternal antibodies do not persist in the offspring for more than 3 months. Based on the neutralising serum antibody titres, we assume that piglets of wild sows vaccinated orally twice or immunised once a long time before conception have protective antibodies for approximately 2 months. Furthermore, it seems that the level and the duration of maternal antibodies in the offspring are depend on the age of the female animals at the moment of vaccination as demonstrated in our experiment. The recent vaccination procedure consists of three double vaccinations in spring, summer and autumn. Especially vaccinations in summer and autumn could be crucial for transfer of high maternal antibody titres to the offspring.  相似文献   

Development of a rapid and sensitive RT-PCR method for the detection of deformed wing virus, a pathogen of the honeybee (Apis mellifera)     

Genersch E 《Veterinary journal (London, England : 1997)》2005,169(1):121-123

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Ultrasonographic anatomy of abdominal lymph nodes in the normal cat.     

Elke Schreurs  Kathelijn Vermote  Virginie Barberet  Sylvie Daminet  Heike Rudorf  Jimmy H Saunders 《Veterinary radiology & ultrasound》2008,49(1):68-72

Lymph nodes are essential structures to be evaluated in an ultrasonographic examination of the feline abdomen. It was hypothesized that current technical proficiency would allow all feline abdominal lymph nodes to be identified ultrasonographically. Ten clinically normal, adult, domestic shorthair cats were examined using real-time compound ultrasonographic imaging. The medial iliac lymph nodes were visible in 100% of the cats, the jejunal lymph nodes in 90%, the hepatic lymph nodes in 70%, the aortic lumbar, the splenic, and the pancreaticoduodenal lymph nodes in 60% each, the ileocecal and the colic lymph nodes in 50% each, and the renal, the gastric, the sacral and the caudal mesenteric lymph nodes in 40%, 30%, 20%, and 10% of the cats, respectively. The inconsistent presence of lymph nodes, their poor echocontrast and interposed gas of the gastrointestinal tract explain the lower percentages of identification. The ultrasonographic length and diameter of the lymph nodes were determined. The majority of these measurements corresponded to those in the literature. We conclude that ultrasonography is a valuable tool for the identification and evaluation of most abdominal lymph nodes in the normal cat. Average ultrasonographic measurements are presented as a preliminary guideline for normal feline abdominal lymph nodes. ete  相似文献   

Carriage of meticillin‐resistant staphylococci between humans and animals on a small farm          下载免费PDF全文

Andrea Klang  Regina Wagner  Theresia Licka  Tom Grunert  Andrea T. Feßler  Dorothe Geier‐Dömling  Renate Rosengarten  Elke Müller  Annett Reissig  Stefan Monecke 《Veterinary dermatology》2016,27(3):191-e48

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Metabolic response of Medicago sativa to severe nutrient imbalances and disturbances under field conditions          下载免费PDF全文

Thomas Fester  Ines Merbach  Elke Schulz  Claus Härtig 《植物养料与土壤学杂志》2014,177(2):245-259

Our experiments were focused on the metabolic footprint of mineral‐nutrient availability under field conditions. While there are multiple factors potentially blurring such footprints, we hypothesized that physiological and metabolic adaptations of established plants are particularly important mechanisms under field conditions. To study respective differences between young and established plants and to study the impact of disturbances on the adaptive capacity of established plants, we analyzed Medicago sativa plants of different age from plots with marked differences in the levels of soil mineral nutrients established in a long‐term fertilization experiment. Gas chromatography–mass spectrometry was used to determine metabolite profiles of sink and source leaves of plants in an early state of development (“young plants”), just before the first harvest (“established plants”), and a short time after the second harvest (“regrowing plants”). Metabolite profiles from young plants were markedly responsive to soil mineral nutrients and resembled respective profiles from controlled conditions, demonstrating that overall variability of growth and sampling conditions had relatively little importance for the metabolite profiles recorded. In the case of established plants, however, we observed only little impact of availability of mineral nutrients on metabolite profiles. This low metabolic responsiveness of plants was partially lost after severe disturbances (removal of the plant shoot). Metabolite profiling, in summary, is able to detect a metabolic footprint of mineral‐nutrient availability in young plants under field conditions and may provide information about the ability of older plants to partially uncouple their metabolism from the environment. In addition, it is also possible to determine the impact of disturbances on this ability of the plant organism.  相似文献