Impact of cropping system on mycorrhiza

The impact of cropping system on field communities of mycorrhizal fungi was studied utilising a long-term experiment on a loamy soil. Two contrasting crop rotations each with two fertilisation regimes were compared. The conventional crop rotation (barley-barley-rye-oat-potato-oat) was fertilised at either full or half the normal recommended rate. In the low-input crop rotation, one year with barley was replaced by clover, and oat was cultivated in mixture with pea. For this rotation biotite and raw phosphate was used to compensate for the K and P of the harvested yield; animal manure was used at the beginning only. Clover and straw were returned to the soil either directly or after composting. Mycorrhizal infectivity and effectiveness were studied in bioassays in the growth chamber, and the spore densities of mycorrhizal fungi as well as their species composition in the field were determined. Only the low-input system with application of compost conclusively favoured mycorrhiza, in comparison to some or all of the other systems depending on time and function. The low-input system with no compost was more favourable than the conventional systems in terms of growth effect in 1996, but in 1997, clover incorporation markedly inhibited mycorrhiza in comparison to the other systems. Inhibition of mycorrhizal functions may indicate general mismanagement and imbalance in the soil ecosystem. This stresses the need for further studies on the importance of composting easily decomposable organic matter prior to soil incorporation for management of soil quality

Performance of AM fungi in peat substrates in greenhouse and field studies

The impacts of peat on mycorrhizal traits has been studied in several field and greenhouse experiments at MTT Agrifood Research Finland In the field experiments, AMF traits were affected by cropping systems and preceding crops but also by peat amendment. Peat had a negative impact on mycorrhizal effectiveness and AMF spore numbers, but did not affect species frequency or the Shannon-Wiener diversity index

Arbuscular mycorrhiza as part of sustainable agriculture

Here we present some results from two studies of mycorrhizal functioning in conventional vs. organic agriculture and also of the impact of various standing crops

Conditions for irrigation with brackish water in Sweden : effects on soil and crop

Detta ex-jobb behandlar för- och nackdelar med användningen av bräckt vatten till odlingsändamål i Sverige. Det svenska klimatet som lantbrukare måste förhålla sig till är relativt hållbart men varma och torra perioder tycks bli alltmer återkommande. Diskussionen kring hur skörden skall försäkras blir då återigen aktuell under dessa perioder, men många av dessa lantbrukare har inte möjligheten att ta upp eller lagra in sötvatten till bevattningsändamål. De söker sig då till alternativa bevattningsmedel vilket ofta leder till Östersjön. Nyttjandet av bräckt vatten till bevattning är ingen ny idé utan har använts i stor utsträckning under 70- och 80-talet. Rationaliserandet av bevattningssystem och anläggningar gjorde det betydligt billigare att bygga och bevattna större arealer. Men nu som då hade inte alla tillgång på sötvatten. Bräckt vatten från Östersjön användes då i stället, mest kring Öland och Gotland till sockerbetsodling. Som mest bevattnades 10 % av den använda arealen på Öland med bräckt vatten. Flera försök och studier gjordes också under denna period då intresset för användningen var stor men kunskapen kring påverkan av bevattning efter svenska förhållanden var liten. Resultatet av studierna visade att bevattning med bräckt vatten under vissa förutsättningar kunde tillföra skadliga mängder salt och natrium vilket påverkar både jorden och grödan. En bevattning med bräckt vatten på 30 mm som har 6 promille i salthalt tillför totalt drygt 1,8 ton salt/ha, större delen utgörs av koksalt som är lättlösligt. En sådan tillförsel av salt i markprofilen kan under vissa förhållanden bidra till minskad skörd genom försämrad markstruktur eller ett större osmotiskt tryck. Men salt är inte det enda som tillförs vid bevattning med bräckt vatten, även natrium och andra joner som kan vara skadliga vid ackumulering tillförs. Natrium som är en katjon kan vid stor anrikning tränga ut och byta plats med andra viktiga katjoner i jorden såsom Ca2+ och Mg2+ . Blir natrium dominerande bland katjonerna kan detta rubba grödornas näringsomsättning och förstöra jordens struktur. Många internationella institutioner skulle avråda användning av östersjövatten till bevattning i sina egna länder, dock har vi ett väldigt humid klimat i Sverige som motverkar effekterna av saltanrikning. Nederbörd eller bevattning med sötvatten som bidrar till ett överskott av vatten i jordprofilen löser saltet och transporterar koncentrationen vidare längre ned och ut ur jorden. Sötvatten hjälper också till att urlaka bundet natrium samt andra joner i markvätskan. Försök med bevattning av bräckt vatten på Öland konstaterade att så länge det fanns ett överskott på nederbörd varje år lyckas inte saltet ackumuleras i rotzonen utan urlakas kontinuerligt ut ur jorden. Tillförseln av sötvatten efter bevattning med bräckt vatten är därför väsentligt för att motverka skador och kunna bruka jorden hållbart. Om detta inte möts och bevattning fortgår kommer bevattningen göra mer skada än nytta.This paper deals with the pros and cons of using brackish water for irrigation purposes in Sweden. The Swedish climate that farmers have to adapt to is relatively stable, but hot and dry periods seem to be increasingly recurring. The discussion how to secure the harvest becomes again relevant during these periods, but many of these farmers do not have the opportunity to collect or store fresh water for irrigation purposes. Therefore, many are looking for alternative irrigations sources, which often leads to the Baltic Sea. The use of brackish water for irrigation purposes is not a new idea but was already used in large scale during the 70- and 80s. The modernization of irrigation systems made it significantly cheaper to build and irrigate larger areas. But like now everyone had not access to fresh water. Brackish water from the Baltic Sea was then used instead, mostly around Öland and Gotland for sugar beet production. At its peak was 10% of all irrigated land on Öland watered with brackish water. Several trials and studies were also done during this period, mostly because knowledge around irrigation with brackish water under Swedish conditions was limited. The results of the studies revealed that irrigation with brackish water could under certain conditions add harmful amounts of salt and sodium, which affects both the soil and the crop conditions. An irrigation with brackish water of 30 mm, with a salinity level around 6 mg/L adds a total of 1.8 tons of salt per hectare, the majority of which consists of common salt that is easily soluble. Such a concentration of salt in the soil profile can under certain conditions contribute to reduced yields due to deteriorating soil structure or increased osmotic pressure. But salt is not the only thing that is added when irrigating with brackish water, sodium and other ions can also be harmful when accumulating. Sodium, which is a cation, can penetrate and change places with other important cations in the soil such as Ca2+ and Mg2+ when enriched greatly. If sodium becomes dominant among the cations it can disrupt the crops' nutrient metabolism and destroy the soil's structure. Many International institutions would discourage the use of Baltic Sea water for irrigation in their own countries, however, Sweden has a very humid climate that counteracts the effects of salt enrichment. Precipitation or irrigation with fresh water that contributes to an excess of water in the soil profile dissolves the salt and transports the concentration further down and out of the soil. Fresh water also helps to leach bound sodium and other ions in the soil. Experiments with irrigation of brackish water on Öland found that if there was an excess of precipitation each year, the salt did not accumulate in the root zone but was continuously leached out of the soil. The application of fresh water after irrigation with brackish water is therefore essential to counteract damage. If this is not met and irrigation continues, the accumulation and concentration of salt will do more harm than good for the crop

Hög skördepotential hos jordgubbe i ekologisk odling beror på markens biologiska egenskaper

Ett långliggande fältförsök med olika odlingssystem utnyttjades för jämförelse av skördepotentialen hos jordgubbe i konventionell respektive ekologisk odling. Skördepotentialen var högre på de ekologiskt odlade försöksytorna och kunde höjas ännu med genom tillförsel av torv

Damping-off of sugar beet with special reference to the fungus Pythium Pringsheim

In Finland damping-off of sugar beet can be divided into two distinct phases. The first phase begins with the germination of the seeds and continues until the first true leaves have developed. Under field conditions seedlings usually remain healthy up to about 1 week after emergence. Thereafter a sudden outbreak of damping-off may occur, resulting in rapid wilting and death of seedlings. During the second phase of the disease, when seedlings have one or more pairs of true leaves, disease does not always result in the death of the plant; plants may survive throughout the summer. At the pernicious phase of the disease the soil borne pathogen, Pythium debaryanum auct. non Hesse, is the most common causal agent, accounting in 1979—86 for 53.9 % (variation between years 18.3—90.1 %) of fungal isolations, and Fusarium species for 28.3 % (5.0—58.5 %). At seedling stages with one or more pairs of true leaves Fusarium spp. predominate accounting for 49.4 % (36.1—81.0 %) as compared to 23,9 % (2.9—37.8) for P. debaryanum. The importance of Fusarium species as true damping-off pathogens is, however, doubtful. The seed borne damping-off pathogen Phoma betae Frank was isolated only in 0 to 4 % and was not dependent on the stage of seedling development. Of the factors affecting damping-off, high temperatures were repeatedly shown to increase the disease. This, presumably was an effect especially on P. debaryanum, the aggressiveness of which is strongly increased at high temperatures. Pot experiments showed preceding crops of cereals to have the best disease-decreasing effect, both short-term (one growing period of preceding crop) and long-term (several growing periods of preceding crop) effect. Legumes kept the level of damping-off unchanged or even raised it, especially as a short-term effect. The influence of preceding crops varied in different soil types. Preceding crops also caused considerable fluctuations in inoculum density (0 to 3650 propagules/gram soil) and potential (0.2—16 IPU 50/gram soil) of Pythium. The correlation to damping-off of sugar beet was, however, poor. Seed treatment with the systemic fungicide hymexazol, especially when combined with thiram, prevented satisfactorily the pernicious type of damping-off. In many experiments this seed treatment repeatedly decreased disease incidence significantly, produced denser stands (7100—31200 numbers of beets more/hectare) and increased yield by 5—10 % on average

Executive functions and successful behavior

Executive functions are the underlying mechanisms that drive top-down regulation of information processing. While suboptimal executive functions have been investigated in various groups of patients, their impact and contribution to behavioral success have not been clarified. It has been suggested that executive functions can be divided into simple executive functions, sometimes referred to as core executive functions, and more complex executive functions often involving other cognitive components referred to as higher order executive functions. Several cohorts of healthy individuals (in total 324 individuals) were investigated in five separate studies (Study I-V) to better understand how higher order executive functions are associated with successful human behavior. Due to its similarity to evolutionary conserved behaviors that depend on well-developed executive functions, including cognitive flexibility and creative fluency, and as well as due to its global impact, soccer was chosen for the three first studies. Soccer is practiced in a strictly controlled area with clear and common rules all around the world. It involves fast problem solving with the aim to reach the same goal in different ways. Soccer is also played by individuals of both sexes of widely different ages and has a shared understanding of how success is defined by both professionals and the audience. Soccer is therefore a good research arena to better understand how executive functions impact human behavior in constantly changing environments where individuals act as free agents but with a common goal and specific restrictions. Study I suggested that elite soccer players show significantly higher executive functions capacity than players on semi-elite level as well as compared to norms of the test. This result was conceptually repeated in Study III, in which national team players were compared with elite players from the same soccer clubs that had never been selected to play in national teams. The difference was especially evident when studying cognitive flexibility and creative fluency using the Design Fluency Test suggesting a better capacity for behavior adjustment. Moreover, this executive functions capacity was related to the number of scored goals and/or made assists under a prolonged measured period. Finally, cognitive flexibility correlated significantly on a moderate level with coach-rated game intelligence, i.e. the players’ ability to “read the game”, to anticipate the intentions of the opposite player and use that information to make successful decisions and actions. The main results from Study I and III were also shown for junior academy players, age range twelve to nineteen years, in Study II. Working memory (a core executive functions) had the most prominent role, suggesting a relation of the results to the maturation of the brain. Both core and higher order EF, but not IQ-measurements, significantly correlated on a moderate level with the number of scored goals the players made during two sessions. The next step was to assess the involvement of higher order executive functions in other nonsport situations where similar cognitive functions also may have a decisive role for success. Study IV showed that applicants for the Swedish counterterror intervention unit (Nationella Insatsstyrkan) had significantly better results in Design Fluency Test compared to average of the population and to police officer trainees mirroring the difference in level of play in soccer. Moreover, following the baseline tests, the applicants were re-tested after significant physical and psychological stress. The results showed that their re-test results declined compared to the expected result. However, there was still a significant correlation between the baseline results and the re-test results, indicating that higher capacity of executive functions could work as a resilience factor and safeguard adequate decision-making under stress. Finally, in Study V, different occupations in a medium sized company including forklift operators, sellers, operational and strategic managers were studied. The results showed that the capacity of cognitive flexibility and fluent creativity (both on a perceptual and a verbal level) correlated negatively with the amount of sick leave for the previous five years. The results remained after controlling for age, work group, sex, and other different cognitive components. Since we adjusted for work group, education and socio-economic factors, these did likely not explain the results. All together this thesis suggests that higher order of executive functions are important factors for success in several human behaviors and occupations. The results may need independent replication but this research project offers novel insights into how EF capacity is associated with behavioral success and that executive functions may represent a resilience factor to stress

A compatibilist computational theory of mind

This thesis defends the idea that the mind is essentially computational, a position that has in recent decades come under attack by theories that focus on bodily action and that view the mind as a product of interaction with the world and not as a set of secluded processes in the brain. The most prominent of these is the contemporary criticism coming from enactivism, a theory that argues that cognition is born not from internal processes but from dynamic interactions between brain, body and world. The radical version of enactivism in particular seeks to reject the idea of representational content, a key part in the computational theory of mind. To this end I propose a Compatibilist Computational Theory of Mind. This compatibilist theory incorporates embodied and embedded elements of cognition and also supports a predictive theory of perception, while maintaining the core beliefs pertaining to brain-centric computationalism: That our cognition takes place in our brain, not in bonds between brain and world, and that cognition involves manipulation of mental representational content. While maintaining the position that a computational theory of mind is the best model we have for understanding how the mind works, this thesis also reviews the various flaws and problems that the position has had since its inception. Seeking to overcome these problems, as well as showing that computationalism is still perfectly compatible with contemporary action and prediction-based research in cognitive science, the thesis argues that by revising the theory in such a way that it can incorporate these new elements of cognition we arrive at a theory that is much stronger and more versatile than contemporary non-computational alternatives

Uudet tekniikat käyttöön avomaalla

Avomaan vihannesviljely kamppailee monien kannattavuutta nakertavien ongelmien puristuksessa. Viljelytekniikoiden kehittäminen on haastavaa, sillä hintojen vertailu osoitti viime kesänäkin, että esimerkiksi kerä- ja kukkakaali oli elokuussa Suomessa jopa halvempaa kuin Hollannin suurissa huutokauppahalleissa. AVIKE-hankkeen päätösseminaarissa 31.8. Hyvinkäällä etsittiin keinoja avomaan vihannestuotannon kilpailukyvyn parantamiseen.vo