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Wendling M.,Institute for Plant Production science | Wendling M.,ETH Zurich | Buchi L.,Institute for Plant Production science | Amosse C.,Institute for Plant Production science | And 3 more authors.
Agriculture, Ecosystems and Environment | Year: 2017

Growing mixtures of species instead of sole crops is expected to increase the ecosystem services provided by cover crops. This study aimed at understanding the interactions between species and investigating how they affect the performance of the mixture. Four species were combined in six bispecific mixtures in a field experiment. The performance of each species when grown in a mixture was compared to its performance as a sole crop at different sowing densities, to characterise the influence of intra- and interspecific competition for each species. Intra- and interspecific competition coefficients were quantified using a response surface design and the hyperbolic yield-density equation. Interactions between the four species ranged from facilitation to competition. Most of the mixtures exhibited transgressive overyielding. Without nitrogen (N) fertilisation, high complementarity between species allowed to achieve the highest biomass. With N fertilisation, high dominance of one mixture component should be avoided to achieve good performance. A revised approach in the use of the land equivalent ratio for the evaluation of cover crop mixtures is also proposed in this study. It allows to better identify transgressive overyielding in mixtures and to better characterise the effect of one species on the other within the mixture. © 2017 The Authors


PubMed | University of Turin and Institute for Plant Production science
Type: Journal Article | Journal: Journal of the science of food and agriculture | Year: 2016

The raspberry, Rubus idaeus L., provides several plant parts (as buds) used for food supplements. The aim of this research was to establish a technique for chemical composition control of R. idaeus herbal preparations, using chromatographic methods. These methods allowed us to identify and quantify the main phytochemicals, obtaining a specific phytochemical fingerprint (phytocomplex). Combined with two different chemometric methods-clustering analysis and principal component analysis-the raspberry bud extracts of the different cultivars were efficiently characterized.Rubus idaeus buds were identified as a rich source of anti-inflammatory and antioxidant compounds: organic acids, vitamins and catechins were found to be the most discriminating variables by chemometric techniques to differentiate raspberry cultivars. In particular, catechins (13.25%) and flavonols (8.71%) were the most important polyphenolic classes, followed by cinnamic and benzoic acids.This study developed a useful tool for R. idaeus extract phytochemical characterization that could be applied also for differentiation and composition control of other herbal preparations. 2015 Society of Chemical Industry.


PubMed | University of Girona, Institute for Plant Production science, Ghent University, Justus Liebig University and 2 more.
Type: | Journal: International journal of systematic and evolutionary microbiology | Year: 2016

A survey to obtain potential antagonists of pome fruit tree diseases yielded two yellow epiphytic bacterial isolates morphologically similar to Pantoea agglomerans, but showing no biocontrol activity. Whole-Cell MALDI-TOF mass spectrometry and analysis of 16S rRNA and gyrB gene sequences suggested the possibility of a new species with a phylogenetic position in either Pantoea or Erwinia. Multilocus sequence analysis (MLSA) placed the two strains in the genus Erwinia and supported their classification as a novel species. The strains showed general phenotypic characteristics typical of this genus and results of DNA-DNA hybridizations confirmed that they represent a single novel species. Both strains showed a DNA G+C content, as determined by HPLC, of 54.5 mol% and could be discriminated from phylogenetically related species of the genus Erwinia by their ability to utilize potassium gluconate, potassium 2-ketogluconate, D-maltose, D-melibiose and D-raffinose. Whole-genome sequencing of strain EM595T revealed the presence of a chromosomal carotenoid biosynthesis gene cluster similar to those found in Cronobacter and Pantoea spp. that explains the pigmentation of the strain, which is atypical for the genus Erwinia. Additional strains belonging to the same species were recovered from different plant hosts in three different continents, revealing the cosmopolitan nature of this epiphyte. The name Erwinia gerundensis sp. nov. is proposed, with EM595T (= LMG 28990T; = CCOS 903T) as the designated type strain.


PubMed | Institute for Sustainability science, Institute for Plant Production science and University of Zürich
Type: Journal Article | Journal: Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment | Year: 2016

Fusarium head blight is one of the most important cereal diseases worldwide. Cereals differ in terms of the main occurring Fusarium species and the infection is influenced by various factors, such as weather and cropping measures. Little is known about Fusarium species in barley in Switzerland, hence harvest samples from growers were collected in 2013 and 2014, along with information on respective cropping factors. The incidence of different Fusarium species was obtained by using a seed health test and mycotoxins were quantified by LC-MS/MS. With these techniques, the most dominant species, F. graminearum, and the most prominent mycotoxin, deoxynivalenol (DON), were identified. Between the three main Swiss cropping systems, Organic, Extenso and Proof of ecological performance, we observed differences with the lowest incidence and toxin accumulation in organically cultivated barley. Hence, we hypothesise that this finding was based on an array of growing techniques within a given cropping system. We observed that barley samples from fields with maize as previous crop had a substantially higher F. graminearum incidence and elevated DON accumulation compared with other previous crops. Furthermore, the use of reduced tillage led to a higher disease incidence and toxin content compared with samples from ploughed fields. Further factors increasing Fusarium infection were high nitrogen fertilisation as well as the application of fungicides and growth regulators. Results from the current study can be used to develop optimised cropping systems that reduce the risks of mycotoxin contamination.


PubMed | Institute for Sustainability science, Institute for Plant Production science and CSIC - Institute of Natural Resources and Agriculture Biology of Seville
Type: Journal Article | Journal: Journal of agricultural and food chemistry | Year: 2016

Metabolism of chiral pesticides in crops is typically studied using achiral analytical methods and, consequently, the stereoisomer composition of residues is unknown. In this study, we developed an enantioselective GC-MS/MS method to quantify residues of the fungicides fenpropidin, fenpropimorph, and spiroxamine in plant matrices. In field trials, the fungicides were applied to grapevines, sugar beets, or wheat. Fenpropidin was metabolized with no or only weak enantioselectivity. For fenpropimorph, slightly enantioselective metabolism was observed in wheat but more pronounced in sugar beets. This enantioselectivity was due to different rates of metabolism and not due to interconversion of enantiomers. The four stereoisomers of spiroxamine were also metabolized at different rates, but selectivity was only found between diastereomers and not between enantiomers. trans-Spiroxamine was preferentially degraded in grapes and cis-spiroxamine in wheat. These findings may affect the consumer dietary risk assessment because toxicological end points were determined using racemic test substances.


Gulkowska A.,Institute for Plant Production science | Buerge I.J.,Institute for Plant Production science | Poiger T.,Institute for Plant Production science | Kasteel R.,Institute for Plant Production science
Pest Management Science | Year: 2016

BACKGROUND: Convincing experimental evidence suggests increased sorption of pesticides on soil over time, which, so far, has not been considered in the regulatory assessment of leaching to groundwater. Recently, Beulke and van Beinum (2012) proposed a guidance on how to conduct, analyse and use time-dependent sorption studies in pesticide registration. The applicability of the recommended experimental set-up and fitting procedure was examined for two fungicides, penflufen and fluxapyroxad, in four soils during a 170 day incubation experiment. RESULTS: The apparent distribution coefficient increased by a factor of 2.5-4.5 for penflufen and by a factor of 2.5-2.8 for fluxapyroxad. The recommended two-site, one-rate sorption model adequately described measurements of total mass and liquid phase concentration in the calcium chloride suspension and the calculated apparent distribution coefficient, passing all prescribed quality criteria for model fit and parameter reliability. CONCLUSION: The guidance is technically mature regarding the experimental set-up and parameterisation of the sorption model for the two moderately mobile and relatively persistent fungicides under investigation. These parameters can be used for transport modelling in soil, thereby recognising the existence of the experimentally observed, but in the regulatory leaching assessment of pesticides not yet routinely considered phenomenon of time-dependent sorption. © 2016 Society of Chemical Industry.


Ancay A.,Institute for Plant Production Science | Carlen C.,Institute for Plant Production Science
Acta Horticulturae | Year: 2016

To compare two training systems and three red currant cultivars ('Red Poll', 'Rovada', 'Tatran') a trial was carried out in Switzerland in Bruson at 1100 m a.s.l. The considered training system for red currant production were: i) the traditional cordon training system (palmette system) with 3 not removed cordons (main branches) and 15 to 20 medium sized lateral braches per plant and ii) the V-training system with constantly renewed cordons, i.e., cordons were removed after 3 years at their basis (no permanent wood) and every year, 3 new cordons were established in order to obtain 2- and 3-year-old cordons producing fruits (V-system). The results over 7 years revealed that the V-training system had little influence on yield, cluster attributes and fruit quality, but a very positive incidence on the picking efficiency with 11% more fruits harvested per hour and on training investments with 15% less training hours. The economic performance of the new V-system was in average of the three cultivars 13% better than the traditional cordon system (palmette). 'Rovada' and 'Tatran' were more productive than 'Red Poll', mainly due to a higher number of clusters per plant. The economic performance was best for 'Rovada' and 'Tatran' grown in V-system.


Buerge I.J.,Institute for Plant Production science | Bachli A.,Institute for Plant Production science | Heller W.E.,Institute for Plant Production science | Keller M.,Institute for Plant Production science | Poiger T.,Institute for Plant Production science
Journal of Agricultural and Food Chemistry | Year: 2015

Haloxyfop-methyl is a chiral herbicide against grasses in dicotyledonous crops. In plants and soil, haloxyfop-methyl is rapidly hydrolyzed to haloxyfop-acid, whose R-enantiomer carries the actual herbicidal activity. In soil, S-haloxyfop-acid is converted within less than 1 day and almost completely into R-haloxyfop-acid. In this study, we investigated the possible interconversion of the enantiomers of haloxyfop-methyl and haloxyfop-acid in blackgrass and garden cress. Racemic or enantiopure haloxyfop-methyl was applied to the leaves of plants grown in agar. The metabolism was followed during 4 days using enantioselective GC-MS. In contrast to soils, no interconversion was observed in plants, and metabolism was nonenantioselective. These findings are consistent with the fact that after pre-emergence application to soil and uptake by roots, the observed herbicidal effect is basically independent of the enantiomer composition of the applied substance, whereas after postemergence application, the efficacy clearly is different for the two enantiomers. © 2015 American Chemical Society.


Poiger T.,Institute for Plant Production science | Muller M.D.,Institute for Plant Production science | Buser H.-R.,Institute for Plant Production science | Buerge I.J.,Institute for Plant Production science
Journal of Agricultural and Food Chemistry | Year: 2015

Haloxyfop-methyl is a chiral herbicide that was first introduced as racemate and later replaced by "haloxyfop-P-methyl", mainly consisting of the R-enantiomer, which carries the herbicidal activity. We studied the ester cleavage of haloxyfop-methyl and further degradation and chiral inversion of the acid enantiomers in three different soils using enantioselective gas chromatography-mass spectrometry. Our results confirm the rapid ester hydrolysis of haloxyfop-methyl with half-lives of a few hours and indicate that hydrolysis is weakly enantioselective. Further degradation of haloxyfop was slower with half-lives of several days. In all three soils, S-haloxyfop was rapidly converted to R-haloxyfop. In sterile soil, no degradation and no inversion were observed, indicating that both processes are biologically mediated. In soil where 50% of the water had been replaced by deuterium oxide, significant H-D exchange in haloxyfop was observed, pointing to a reaction mechanism involving abstraction of the proton at the chiral center of the molecule. © 2015 American Chemical Society.


PubMed | Institute for Plant Production science
Type: Journal Article | Journal: Pest management science | Year: 2016

Convincing experimental evidence suggests increased sorption of pesticides on soil over time, which, so far, has not been considered in the regulatory assessment of leaching to groundwater. Recently, Beulke and van Beinum (2012) proposed a guidance on how to conduct, analyse and use time-dependent sorption studies in pesticide registration. The applicability of the recommended experimental set-up and fitting procedure was examined for two fungicides, penflufen and fluxapyroxad, in four soils during a 170 day incubation experiment.The apparent distribution coefficient increased by a factor of 2.5-4.5 for penflufen and by a factor of 2.5-2.8 for fluxapyroxad. The recommended two-site, one-rate sorption model adequately described measurements of total mass and liquid phase concentration in the calcium chloride suspension and the calculated apparent distribution coefficient, passing all prescribed quality criteria for model fit and parameter reliability.The guidance is technically mature regarding the experimental set-up and parameterisation of the sorption model for the two moderately mobile and relatively persistent fungicides under investigation. These parameters can be used for transport modelling in soil, thereby recognising the existence of the experimentally observed, but in the regulatory leaching assessment of pesticides not yet routinely considered phenomenon of time-dependent sorption. 2016 Society of Chemical Industry.

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