1,853 research outputs found
Relation between growth characteristics and yield of barley in different environments
The increasing interest in organic farming has increased the interest in examining the importance of the different growing characteristics, such as attack of diseases, grain weight, lodging and heading date. One of the important questions raised was whether the relationship between the growing characteristics and yield would be the same for conventionally and organically grown crop or would some growing characteristics be more important for organically than for conventionally grown crops. This work will focus on that question.
The analyses are performed using two datasets with comparable trials in both conventional and organic grown systems for barley (Hordeum vulgare). The two datasets were from Sweden and Denmark. From Sweden 22 conventional and 22 organic grown trials were available. The trials were laid out at 4 locations in Northern Sweden during the years from 1994-2003. The number of varieties per trial varied between 7 and 15 and 50 varieties were represented. Most of the trials were laid out as split-plot designs with 2 nitrogen levels in the conventional grown trial and 2 seed rates in the organic grown trials. From Denmark 4 conventional and 4 organic grown trials were available. The trials were laid out as a-designs at 2 locations in 2 years (2003 and 2004).
The number of varieties per trial varied between 108 and 113 and 146 varieties were represented. The data from each country were analysed in a linear mixed model. The effects of location, year, variety, their interaction and interaction with system were included as random effect. The effect of growing system and growing characteristics were included as fixed effects to see how much of the variation caused by varieties and interaction with varieties that could be explained by the growing characteristic and to se if the effect of the growing characteristics depended on the growing system.
The analyses showed that the growing characteristics could explain a considerable part of the variance components for variety or interaction with variety. The effect of some growing characteristics depended significantly on the growing system, but the results varied to some extent between the two countries. In Sweden the effect of volume weight were more important in the conventional grown trials than in the organic grown trials whereas in Denmark grain weight was more important in the organic grown trials than in the conventional grown trials. In Denmark powdery mildew decreased the yield significantly more in conventional grown trials than in organic grown trials. In most cases the other diseases decreased the yield more in the organic grown trials than in the conventional grown trials. In some models the yield in organic grown trials increased as the level of scald attach increased. The results indicated that the effect of a given disease level decreased the yield more in the conventional grown trials than in the organic grown trials – or in some cases increased the yield in the organic grown trial while the yield in conventionally grown trials were increased less or decreased
Spore contamination of Tilletia tritici in seed lots as affected by field disease incidence
Seed lots normally become contaminated by spores of the seed borne common bunt (Tilletia tritici) during harvest of fields with infected plants. To demonstrate the relation between the number of infected plants in the field and the resulting number of spores in the harvested seed lot, a fixed number of infected tillers were placed in uncontaminated wheat fields. Two field experiments show
that the number of spores in the seed lot is proportional to the number of infected plants in the field. Only 3% of the spores from the infected plants in the field end up in the seed lot after harvest with a combine harvester. However, only few spores in a seed lot is enough to establish infection in the next year field, and with a threshold of 10 spores/g seed which is the current threshold for untreated seed in Denmark, less than 1 infected tiller per 1000 m2 can be accepted in a field aimed for propagation
A model analysis on nitrate leaching under different soil and climate conditions and use of catch crops
The use of crops and catch crops with deep rooting can strongly improve the possibility of retaining nitrate-N that will otherwise be leached to the deeper soil layers and end up in the surrounding environment. But will it always be an advantage for the farmer to
grow a catch crop? This will depend on factors such as soil mineral nitrogen level, soil water holding capacity, winter precipitation, rooting depth and N demand of the scceeding crop. These factors interact, and it can be very difficult for farmers or advisors to use this information to decide whether growing a catch crop will be beneficial. To analyse the effect of catch crops under different Danish soil and precipitation conditions, we used the soil, plant and atmosphere model Daisy
Investigating Optimal Progress Measures for Verification of the WebSocket Protocol
The sweep-line method is a state space reduction technique formemory-efficient on-the-fly verification of concurrent systems. Themethod relies on a progress measure capturing inherent progress in thesystem under verification to store only fragments of the state space inmemory at a time and thereby reduce peak memory usage. The sweep-line method has been applied to many concurrent systems, but theoptimality of progress measures in terms of the peak number of statesstored has not been investigated. Assessing the optimality of a progressmeasure is important since memory in most cases is the limiting factorin verification using state spaces. We derive lower bounds for the peaknumber states and present initial experimental results on near optimalprogress measures for verification of the IETF WebSocket protocol
INVESTIGATION OF SEGMENTAL CHARACTERISTICS IN POWERFUL SOCCER HEADING
The aim of this study was to investigate segmental characteristics of the jumping header in soccer, with prime focus on the arms, legs and the head. To accomplish this a standardization of the skill was also created. Five skilled subjects impacted soccer balls delivered at 13.1 [±0.22] m/s from a ball canon. The body and ball movement were video filmed at 120/240 Hz. It was concluded that the head accelerates forward, relative to the torso, throughout the impact phase and that the mass impacting the ball (13.8 % of the whole body mass) was a significant larger mass than the head's mass alone. Furthermore, the segmental angular momentum of the legs indicated that these segments were used mechanically well in the execution of the skill, while this was not the case with the arms. From the development of the segmental velocity and angular momentum throughout the heading phase, it could also be concluded, that the over all timing of the skill was not optimum
Simulating Root Density Dynamics and Nitrogen Uptake -Field Trials and Root Model Approach in Denmark
Plant soil and atmosphere models are commonly used to predict crop yield and associated environmental consequences. Such models often include complex modelling of water movement, soil organic matter turnover and above ground plant growth. However, the root modelling in these models is often very simple, partly due to a limited access to experimental data. Here we propose a root model developed to describe root growth, root density and nitrogen uptake. The model focuses on annual crops, and attempts to model root growth of different crop species and row crops and its significance for nitrogen uptake from different parts of the soil volume
Spiringskvalitet af økologisk såsæd
Artiklen gennemgår problemstillingen omkring vitalitet i økologisk såsæd, og giver anbefalinger til indsatser, der kan forbedre den
‘Russophone Israeli Cinema: “Accented”, Post-Soviet, Transnational, Postnational?’
Source at http://www.kinokultura.com/.This issue focuses on Russophone cinema in Israel, i.e., films made by and about ex-Soviet Israelis in Israel and elsewhere. Our
work on this publication began well before Russia's full-scale invasion of Ukraine on 24 February 2022. Even if the current war has
little bearing on the articles and reviews that are collected here, it is not at all surprising that this particularly horrifying context
leads, inter alia, to reflections on cinema production within a Russian context. These reflections also need to be extended to how
we study post-communist cinema more generally
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