Weed management in cereals with cover crops - do they help of hinder?

Sustainable crop production calls for integrated weed management approaches. Cover crops (CCs) have been studied primarily in the context of soil fertility and soil structure but they might also supplement the weed management toolbox, particularly when adapted to long-term control strategies. The challenge in organic cropping is to provide strong weed suppression without severely compromising weed species diversity and crop yields. Several CC species, mainly sown in mixtures, were studied in organically cropped 3-year field experiments in southern Finland. The study was part of the PRODIVA project (Core Organic Plus 2015-2018) in which crop diversification for better weed management has been studied and presented in the 18th EWRS Symposium

Crumpled textile antennas

The performance of a dual-band textile antenna under two-dimensional crumpling conditions is described. Both input impedance and radiation patterns are investigated based on numerical and experimental methods at 2.45 and 5.8 GHz. The return loss for the coplanar antenna is affected by the most severe crumpling at the higher frequency band, while the radiation patterns remain acceptable at both bands

Overwintering and regrowth of Sonchus arvensis roots in Finland as affected by fragmentation and burial in three different soil types

In this study the effect of root fragmentation, burial depth and soil type on overwintering and regrowth of Sonchus arvensis L. (perennial sow-thistle) was studied

Effect of crop species and management practices on perennial weeds in organic farming

In order to study the biology and non-chemical control of perennial weeds, a three-year field experiment was established in 2001 at Vihti, southern Finland. The experiment was placed in a clay soil field under organic production, infested moderately with Cirsium arvense, Elymus repens and Stachys palustris, and heavily with Sonchus arvensis

Response of Sonchus arvensis to mechanical and cultural weed control

In order to study the biology and physical control of Sonchus arvensis, a 3-year field experiment was established in 2001 at Vihti, southern Finland

Weed flora and weed management of field peas in Finland

The composition of the weed flora of dry pea (Pisum sativum L.) fields and cropping practices were investigated in southwestern Finland. Surveys were done in 2002–2003 in 119 conventionally cropped fields and 64 fields under organic cropping. Herbicides were applied to 92% of conventionally cropped fields where they provided relatively good control but were costly. Weeds were controlled mechanically only in five fields under organic production. A total of 76 weed species were recorded, of which 29 exceeded the 10% frequency level of occurrence. The average number of weed species per field was 10 under conventional cropping and 18 under organic cropping. The most frequent weed species in both cropping practices were Chenopodium album, Stellaria media and Viola arvensis. Elymus repens was the most frequent grass species. The difference in species composition under conventional and organic cropping was detected with Redundancy Analysis. Under conventional cropping, features of crop stand and weed control explained 38.7% and 37.6% of the variation respectively. Under organic cropping the age of crop stand and field location (y co-ordinate) respectively explained best the variation. Weeds could be efficiently managed with herbicides under conventional cropping, but they represented a significant problem for organic production. Mixed cultivation of pea with cereals is recommended, particularly for organic cropping, as it favours crop competition against weeds

More Borda Count Variations for Project Assesment

We introduce and analyze the following variants of the Borda rule: median Borda rule,geometric Borda rule, Litvak’s method as well as methods based on forming linear combinations of entries in the preference outranking matrix. The properties we focus upon are the elimination of the Condorcet loser as well as several consistency-type criteria.Borda rule, median rule, Nash welfare function, outranking matrix, maximin rule, consistency

On the Existence of Markov Perfect Equilibria in Perfect Information Games

We study the existence of pure strategy Markov perfect equilibria in two-person perfect information games. There is a state space X and each period player's possible actions are a subset of X. This set of feasible actions depends on the current state, which is determined by the choice of the other player in the previous period. We assume that X is a compact Hausdorff space and that the action correspondence has an acyclic and asymmetric graph. For some states there may be no feasible actions and then the game ends. Payoffs are either discounted sums of utilities of the states visited, or the utility of the state where the game ends. We give sufficient conditions for the existence of equilibrium e.g. in case when either feasible action sets are finite or when players' payoffs are continuously dependent on each other. The latter class of games includes zero-sum games and pure coordination games.dynamic games, Markov perfect equilibrium

Demented Prisoners

We study infinitely repeated Prisoners' Dilemma, where one of the players may be demented. If a player gets demented in period t after his choice of action, he is stuck to this choice for the rest of the game. So if his last choice was ``cooperate'' just before dementia struck him, then he's bound to cooperate always in the future. Even though a demented player cannot make choices any more he enjoys the same payoffs from strategy profiles as he did when healthy. A player may prove he is still healthy by showing a (costly) health certificate. This is possible only as long as the player really is healthy: a demented player cannot get a clean bill of health. We study an asymmetric information game where it is known that player 1 cannot get demented but player 2 may be either a ``healthy'' type who will never be demented or a ``dementible'' type who eventually will get demented. We study when cooperation can be maintained in a perfect Bayesian equilibrium with at most health check.prisoners' dilemma, dementia, co-operation