Simulating the soil phosphorus dynamics of four long-term field experiments with a novel phosphorus model

Phosphorus is a nonrenewable resource, which is required for crop growth and to maintain high yields. The soil P cycle is very complex, and new model approaches can lead to a better understanding of those processes and further guide to research gaps. The objective of this study was to present a P-submodel, which has been integrated in the existing Carbon Candy Balance (CCB) model that already comprises a C and N module. The P-module is linked to the C mineralization and the associated C-pools via the C/P ratio of fresh organic material. Besides the organic P cycling, the module implies a plant-available P-pool (P_av), which is in a dynamic equilibrium with the nonavailable P-pool (P_na) that comprises the strongly sorbed and occluded P fraction. The model performance was tested and evaluated on four long-term field experiments with mineral P fertilization, farmyard manure as organic fertilizer and control plots without fertilization. The C dynamics and the P_av dynamics were modelled with overall good results. The relative RMSE for the C was below 10% for all treatments, while the relative RMSE for P_av was below 15% for most treatments. To accommodate for the rather small variety of available P-models, the presented CNP-model is designed for agricultural field sites with a relatively low data input, namely air temperature, precipitation, soil properties, yields and management practices. The CNP-model offers a low entry threshold model approach to predict the C-N and now the P dynamics of agricultural soils.     

Über die Wasserbeständigkeit der Bodenkrümel,besonders in Abhängigkeit von Zeit und Bodenfeuchtigkeit: II. Mitteilung: Über die Veränderungender stabilen Krümelanteile in Abhängigkeit von der Bodenfeuchtigkeit

In Gefäß‐ und Inkubationsversuchen wurde die Wirkung steigender teerhaltiger Zusätze auf das Pflanzenwachstum von Gartenkresse (Lepidium sativum L.) sowie das Abbauverhalten dieses Substrates geprüft. Es zeigte sich eine nachteilige Beeinflussung der Pflanzenentwicklung, deren Ausmaß durch die Höhe des Teersubstratzusatzes bestimmt war. Zur Aufklärung des Ursachenkomplexes werden als wesentliche Faktoren flüchtige organische Kohlenwasserstoffe, N‐Immobilisierung und O₂‐Mangel, induziert durch die einsetzende starke CO₂‐Entwicklung, diskutiert.     

Conidial production and viability of Calonectria pseudonaviculata on infected boxwood leaves as affected by temperature,wetness, and dryness periods

Calonectria pseudonaviculata causes lesions on boxwood leaves and twigs. Controlled-environment experiments were conducted to determine the effects of temperature and leaf wetness period on C. pseudonaviculata sporulation on diseased (cv. Suffruticosa) leaves and of dryness periods and high temperature on conidial survival. Infected leaves were incubated in moist chambers and subjected to six temperatures (9, 13, 17, 21, 25, and 29°C) and six leaf wetness periods (0, 12, 24, 40, 48, and 72 h). Spore production was influenced significantly by wetness period, temperature, and their interaction. Increasing duration of leaf wetness and increasing temperature generally increased sporulation, with no sporulation occurring at 29°C or 9 and 13°C, except at 72 h of wetness exposure, while it was optimal at 21°C. Detached leaves with profuse conidia were subjected to a range of drying (relative humidity at 65%) times (0, 2, 4, 6, and 8 h) at two temperatures of 21 and 29°C. Conidia were then harvested and plated on water agar. Germinating conidia were counted to measure the spore viability. Spore mortality increased with increasing dryness duration at both temperatures but occurred more quickly and severely at 29 than 21°C. Overall, this study extended biological knowledge of conditions required for crucial stages of the C. pseudonaviculata disease cycle and the obtained results will be vital for developing boxwood blight forecasting and management tools.     

Breeding for organic agriculture: the example of winter wheat in Austria

Breeding for organic agriculture (BFOA) is a strategy for a commercial breeding company based on the exploitation of the frequently observed high correlation for many traits between conventional, low input (LI) and organic agriculture (ORG). Indirect selection under LI can be useful to roughly divide the germplasm into the genotypes better adapted to high input and those better adapted to LI or ORG conditions. BFOA is an evolving process, in which two methods are currently applied: early generations are either selected following the pedigree system under LI, or grown as bulk populations on ORG fields. In the latter case the system switches to LI after individual ear selection under ORG conditions. In both methods, the first replicated yield trial is grown parallel under ORG and LI. Subsequently, the genotypes are grouped into conventional or ORG advanced trial series. The BFOA strategy allows that the larger genetic variability of both the organic and conventional gene pool can be exploited in the selection for ORG. Hitherto, seven winter wheat varieties were released in Austria after exclusive organic VCU testing.     

Giardia duodenalis in small animals and their owners in Germany: A pilot study

Giardia duodenalis is a relevant gastrointestinal protozoan pathogen of humans and animals. This species complex consists of eight genetically different assemblages. Assemblages A and B are pathogenic to humans and pets, thus confer zoonotic potential. The risk of zoonotic transmission has been controversially discussed. The aim of this monocentric cross‐sectional pilot study was to investigate G. duodenalis assemblages in humans and pets living in common households in Berlin/Brandenburg (Germany). Samples from dogs, cats and humans sharing the same households were screened for Giardia infection by antigen‐detecting assays. All human samples were additionally analysed by a Giardia‐specific qPCR. Cyst quantification and sequences of different gene loci (triosephosphate isomerase (tpi), glutamate dehydrogenase (gdh), β‐giardin (bg) and for dogs SSUrDNA) were analysed. A total of 38 households (31 households with dogs and seven with cats) with 69 human individuals participated in the study. Initial antigen‐detecting assays revealed Giardia‐positive results for 13 (39%) canine, one (14%) feline and one human sample. Reanalysis of the human samples by qPCR revealed two more positive specimens (4%). Two of these three samples were identified as assemblage B at all tested loci. Success rate of assemblage typing for pet samples was generally low and comprised mainly the SSUrDNA locus only. Overall, six of 13 Giardia‐positive canine samples were typable (2× A, 1× co‐infection: A and B, 1× C; 2× D). One pair of samples (dog and human) from the same household had a similar but not identical assemblage B sequence at tpi locus. Assemblage A was also detected in the dog specimen, which hampered sequence analysis. In conclusion, although exhibiting limitations due to the sample size, our study highlights the need for better and standardized typing tools to distinguish G. duodenalis strains with higher resolution in order to perform proper case–control studies for a realistic estimation of zoonotic risk.     

A new dicaffeoylquinic acid butyl ester from Isertia pittieri

A new 4,5-di-O-caffeoylquinic acid butyl ester (1) was isolated from an ethyl acetate soluble fraction of Isertia pittieri stems, along with three known compounds, 1,5-di-O-caffeoylquinic acid (2), 3,4-di-O-caffeoylquinic acid (3) and 4,5-di-O-caffeoylquinic acid (4).     

Ein neuer Holzschädling für Mitteleuropa Der amerikanische Splintholzkäfer (Lyctus planicollis Lec.)

Zusammenfassung Der amerikanische Splintholzkäfer (Lyctus planicollis Lec.) ist in den Jahren 1950 und 1951 aus Nordamerika mit Hickoryholz nach Österreich eingeschleppt worden.Auf Grund des gezüchteten Materials sind Beschreibungen aller Entwicklungsstadien dieses Holzinsekts gegeben und mit Bildern illustriert. Die Durchschnittsgrößen und die Grenzwerte (in Klammern) für Mannchen und Weibchen zusammen lauten: Länge der Imagines 3,2 mm (2,3 bis 5,4 mm), Breite der Imagines 0,8 mm (0,6–1,3 mm), Kopfbreite 0,6 mm (0,5–1,0 mm), Halsschildbreite 0,7 mm (0,5–1,2 mm), Flügeldeckenlänge 2,2 mm (1,8–3,2 mm).Die Flugzeit dauerte im Laboratorium bei Temperaturen zwischen 14 und 25° C und einer relativen Luftfeuchtigkeit von 30–55% vom 14.3. bis zum 8.9. im Jahre 1953 und begann im Jahre 1954 bereits am 5.1. Die Imagines leben 10–35 Tage. Sie sind lichtscheue Tiere; ihre Copula dauert nur einige Sekunden. Die Ausfluglöcher sind kreisrund und messen 0,9–2,0 mm.Die Lebensweise ist ausführlich behandelt.MitLyctus planicollis waren in schwächerem Anteil eineTrogoxylon- und eineBostrychus-Art vergesellschaftet, beide Angehörige der amerikanischen Insektenfauna.Von Parasiten wurde eine BrackwespeMonolexis fuscicornis Foerster (Fam.Braconidae) gezüchtet, die ebenfalls eine amerikanische Art ist.Die Fraßholzarten sind: Hickory-Holz, Walnuß, Eiche, Esche, Ahorn, Ulme, Robinie, Mahagoni-Holz, Sycomore-Holz, Bambusrohr, Pappel und Weide.Die Larven sind nur imstande, die Depots an Stärke, Zucker und Eiweißstoffen aus den Holzzellen sich mittels Symbionten (Bakterien) durch die Fermente Carbohydrasen und Proteasen zu erschließen. Lyctus planicollis tritt sowohl in geschlossenen Räumen als auch auf offenen Lagerpläten auf und befällt die verschiedenartigsten Gegenstände und zwar sowohl Roh- als auch Fertigwaren.Zur Vorbeugung gehört: luftige, trockene, lange Lagerung des Holzes und Bestreichen mit verschiedenartigen Lösungen bzw. Farben.Als Bekämpfung ist zu empfehlen: Mehrstündiges Dämpfen des befallenen Materials bei 65° C (die unterste Grenze liegt bei einer Stunde bei 16 mm Holzstärke) und verschiedene, oben genau angeführte chemische Bekämpfungsmittel.