Einflüsse von Minimalbodenbearbeitung und Transfermulch auf die perennierende Beikrautflora im Kartoffelbau

Reduced tillage enhances soil fertility and can help to avoid erosion. The drawback of increased weed pressure is a challenge for organic farmers due to the prohibition of herbicides. Mulch could be a way to suppress weeds and to introduce reduced tillage systems in potato cultivation. The number of perennial weeds were monitored in a comparison of two potato cultivation systems: conventional ploughing and hilling versus reduced tillage with dead mulch. In 2014, perennial weeds in the mulch system increased to double the number compared to the ploughed system. The reverse pattern was observed in 2015. This reversed effect was due to improved application methods of mulch with smaller particle size and a closer C/N-Ratio in the mulch in 2015 in combination with a severe spring drought in 2015 but not in 2014

An efficient solution procedure for elastohydrodynamic contact problems considering structural dynamics

This work presents an efficient solution procedure for the elastohydrodynamic (EHD) contact problem considering structural dynamics. The contact bodies are modeled using reduced finite element models. Singly diagonal implicit Runge-Kutta (SDIRK) methods are used for adaptive time integration. The structural model is coupled with the nonlinear Reynolds Equation using a monolithic coupling approach. Finally, a reduced order model of the complete nonlinear coupled problem is constructed

Heterogene Weizenpopulationen als Alternative zu kommerziellen Sorten unter ökologischem Management

Interest in heterogeneous crop populations is growing within both the scientific community, as well as with organic farmers. In order to ensure widespread acceptance amongst farmers, agronomic testing of currently available composite cross populations (CCPs) under organic management is necessary. Eleven CCPs were compared to five commercially grown varieties in a two-year field experiment under organic management (2016/17 and 2017/18). The results over the two experimental years indicate that CCPs are a viable and interesting alternative to commercial varieties within organic farming systems

Der Einfluss von reduzierter Bodenbearbeitung und Zwischenfrüchten auf die Unkrautsamenbank nach ökologischem Winterweizen- und Kartoffelbau

Conservation agriculture is one answer to counteract problems that are arising with climate change and soil degradation since the period of agricultural intensification. The main objectives of conservation agriculture are reduction of tillage intensity and a permanent soil cover by cash and cover crops. However, increased weed infestations are frequently reported in minimum tillage systems, particularly under organic management, resulting in increased weed seed banks. In two field experiments introduced in 2010 and 2011 and starting with two years grass-clover followed by winter wheat and potatoes, we evaluated the effect of chisel ploughing with mulch application to potatoes and different cover crops after winter wheat on the weed seed bank. Therefore, soil cores were taken before sowing wheat and after potato harvest and the viable weed seed bank from soil samples was assessed over a nine month period. Our results suggested a strong influence of weather conditions resulting in decreased and increased weed seed banks in the first and second experiments, respectively. Furthermore, winter wheat was confirmed as the main contributor of weed seeds to the seed bank resulting in dominances of winter annual weeds

Effekte von Kompostapplikationen auf Fußkrankheiten und Grünmasseertrag von Wintererbsen

Abstract: Effects of compost applications on foot diseases and biomass yield of winter peas. A field experiment was conducted to assess the effects of compost applications on the growth and health of winter peas from September 2009 to May 2010. A total of 5 t DM ha-1 of a 12 month old yard waste compost were applied in plots that were either uninoculated or inoculated with Phoma medicaginis grown on infested oat kernels. The control treatment received no compost and was left uninocu-lated. Main plots received all four treatments and were replicated four times. Compost slightly reduced the incidence of Mycosphaerella pinodes and Phoma medicaginis in March and the foot disease severity in May. Overall fresh matter production was significantly reduced by inoculation. These reductions were compensated by compost applications. There was great variation among main plots in the performance of the peas. Where peas performed poorly in the controls (i.e. low fresh matter yield) com-posts improved the performance considerably. Where performance was high, there were no more additional benefits of adding compost to the system

Der Einfluss von Minimalbodenbearbeitung, Zwischenfrüchten und Kompostdüngung auf pflanzenparasitäre Nematoden im Ökolandbau

Plant parasitic nematodes (PPN) can be highly damaging towards plants managed organically. In particular, broad host range PPN (Pratylenchus spp., Meloidogyne spp.) increase under long crop rotations and high weed pressure. PPN populations have been monitored since the beginning of an EU-project about minimum tillage, cover crops. living mulches, and compost application in organic farming in 2012. In the first two years after set up of the experiment, a slight increase of PPN in the minimum tillage treatment was found. However, compost as well as cover crops and living mulches did not change PPN populations so far

Das Ertragsniveau von Composite Cross Winterweizenpopulationen mit unterschiedlichen Managementhistorien in zwei Bodenbearbeitungssystemen

Die Züchtung heterogener Composite Cross Populationen (CCPs) und ihre darauffolgende Anpassung an lokal vorherrschende biotische und abiotische Stressfaktoren hat zum Ziel, die Ertragsstabilität und Resilienz des Weizens zu steigern. Die Ertragsleistung von sechs CCPs mit identischem genetischen Hintergrund aber unterschiedlichen Managementhistorien wurde in einem Langzeitversuch mit verschiedenen Bodenbearbeitungs- und Düngungssystemen getestet. Diejenigen CCPs, die seit 2005 konventionell angebaut wurden, erzielten einen signifikant höheren Ertrag unter Pflug- als unter Minimalbodenbearbeitung. Für die seit 2005 ökologisch angebauten CCPs konnte kein signifikanter Ertragsunterschied zwischen den Bearbeitungssystemen festgestellt werden. Die seit 2008 in einem Breitsaatverfahren ohne Unkrautkontrolle angebauten ökologischen CCPs waren sogar tendenziell ertragsstärker unter Minimalbodenbearbeitung. Daraus ergibt sich, dass die jeweiligen Selektionskräfte, die durch langfristiges Management auf die CCPs eingewirkt haben, zu einer unterschiedlichen Anpassung an spezifischen Umweltbedingungen geführt haben

Multi-core Interference-Sensitive WCET Analysis Leveraging Runtime Resource Capacity Enforcement

The performance and power efficiency of multi-core processors are attractive features for safety-critical applications, as in avionics. But increased integration and average-case performance optimizations pose challenges when deploying them for such domains. In this paper we propose a novel approach to compute a interference-sensitive Worst-Case Execution Time (isWCET) considering variable accesses delays due to the concurrent use of shared resources in multi-core processors. Thereby we tackle the problem of temporal partitioning as it is required by safety-critical applications. In particular, we introduce additional phases to state-of-the-art timing analysis techniques to analyse an applications resource usage and compute an interference delay. We further complement the offline analysis with a runtime monitoring concept to enforce resource usage guarantees. The concepts are evaluated on Freescale's P4080 multi-core processor in combination with SYSGO's commercial real-time operating system PikeOS and AbsInt's timing analysis framework aiT. We abstract real applications' behavior using a representative task set of the EEMBC Autobench benchmark suite. Our results show a reduction of up to 75% of the multi-core Worst-Case Execution Time (WCET), while implementing full transparency to the temporal and functional behavior of applications, enabling the seamless integration of legacy applications

Shifts in the composition of plant parasitic nematodes under different tillage sytems, living mulch, and compost application

Plant parasitic nematodes may cause massive yield reductions in organic farming. Long rotations, often high amounts of weeds and a high frequency of legumes favour parasitic nematodes with a broad host range such as Meloidogyne spp. und Pratylenchus spp. The EU- Projekt OSCAR (Optimizing Subsidiary Crop Applications in Rotations) aims at improving soil conservation through minimum tillage combined with living mulches, cover crops and the use of suppressive composts. An experiment was set up with a rotation of 2-year grass-clover mix followed by wheat and then potatoes. Experimental factors were tillage, cover crops, and compost application. Until now Nematodes were sampled before and after wheat and before potatoes. Population dynamics over time were more affected by the time of the year than by the treatments applied. Sampling will continue will be presented Pratylenchus, Meloidogyne und Helicotylechus/Rotylenchus increased in the first year in all treatments. In the first half of the second year it appears that Meloidogyne has increased with no obvious effect of the treatments so far

Organic potatoes, reduced tillage and mulch in temperate climates

The experiments with mulching were done in a systems approach comparing potatoes as they are typically produced in Germany with ploughing to a system of non-inversion tillage combined with mulch. As the plots are integrated in two long-term experiments comparing ploughed versus minimum tillage it was not possible to integrate a mulched ploughed treatment or a non-mulched non-inversion tillage due to restrictions in plot size. We tested the effects of mulching in a ploughed system in 2015. There was no late blight but good erosion control (Pict.5) and yields were increased through mulching. Compost effects on the system were so far not clearly visible. It will most likely take several more years of regular applications to start seeing changes in system performance. Overall, mulching will change the potato system and it will depend very much on the local soil and climatic conditions if and when mulching will be positive (Table 1). On the one hand, mulching is labor intensive and requires the availability of materials to use. Besides freshly cut materials silage is an alternative option some farmers are using in vegetables in Germany. This reduces the dependence on the growing conditions for the mulch early in the season and likely also increases the fertilization effect. Farms that have no animals often mulch grass-clover. This will suppress N-fixation by the clover due to the nutrients in the mulch and thus reduce the usefulness of the grass-clover for nutrient accumulation. In addition it may result in leaching and thus loss of nutrients and even potentially harm the environment. Using the first and most rich harvest as mulch in the potatoes or alternatively making silage for later use is easier than composting such materials. Once the mulch is applied, no more mechanical weed control is done saving labor and energy. More importantly, it will also reduce the mechanical damage done to the potato foliage that makes them more susceptible to infections and it allows for profuse growth of fine roots into the applied mulch materials. Mulching also reduced Colorado potato beetles in both years to some extent but these data need confirmation. Also, the residual effects on the subsequent crop after the potatoes due to the increased input of organic amendments still need to be studied. Ecologically speaking mulching has many advantages. These advantages are especially important in water restricted areas. If and how mulching is feasible and economical depends on the specific conditions and organization of a farm, however