Controlling broad-leaved dock (Rumex obtusifolius) in grass clover mixtures

This article describes three experiments on the control of broad-leaved dock. Experiment 1: Dock seeds were ensiled in grass silages of different dry matter percentages; 23, 34 and 60% respectively. All silages showed a decline of seed vitality in time. Grass clover with dock seeds should be ensiled at a low dry matter percentage or remain in the silage bin for a longer period than 8 weeks. Experiment 2: In a potassium fertilisation trial on grass clover the development of dock was followed. After two years of potassium fertilisation, the number of dock and the root mass was not significant different between the fertilised and the unfertilised plots. It is concluded that potassium fertilisation at a low potassium status does not positively influence the dock development. Experiment 3: In a resown grass clover, dock seedlings were cut at three frequencies; 2, 4 and 6 weeks. After 3 months the number of seedlings had decreased the same in all treatments. However the root biomass of the seedlings was significantly affected. It is concluded that frequent cutting has a negative effect on root biomass but should be practised for a longer period than 12 weeks to have an effect on seedling numbers

Nut & Natuur Overijssel: Meerwaarde, benutting en borging van groene grondstoffen uit natuurgebieden in Overijssel; praktische bijdragen aan een bio-based economy vanuit landbouw en natuurbeheer

In het project “Nut en Natuur Overijssel” zijn in opdracht van de provincie Overijssel innovatieve samenwerkingsverbanden opgezet tussen natuurbeherende organisaties en boeren om de groene grondstoffen uit natuurgebieden te waarborgen. In drie samenwerkingsverbanden is gezocht naar nieuwe vormen van natuurbeheer door boeren, zoals aangepaste voerwinning van schrale natuurgraslanden en -akkers en de verwerking van reststromen uit bijvoorbeeld rietlanden en heide

Natuurherstel in grasland door klaver en kalibemesting

Hoge fosfaatgehalten in bodems van voormalige landbouwgronden staan een snelle natuurontwikkeling in de weg. Het huidige verschralingsbeheer leidt op korte termijn niet tot de gewenste fosfaatverschraling. Het Overlegplatform Duinboeren en het Louis Bolk Instituut hebben in samenwerking met Vereniging Natuurmonumenten de mogelijkheden van ‘uitmijnen’ getoetst door middel van de biologische teelt van grasklaver in het natuurontwikkelingsgebied het Hengstven

Bodemgezondheid in de biologische kasteelt Deel 1: definitiestudie

Bodemkwaliteit is een containerbegrip dat biologische, chemische en fysische componenten omvat. Bodemgezondheid is een nauwer begrip dat beschreven kan worden vanuit een ecosysteem benadering. De begrippen stabiliteit en zelfregulatie, vitaliteit, ecologische veerkracht, organisatiegraad en biodiversiteit worden ten opzichte van elkaar gepositioneerd. Ziektewerendheid is een weer nauwere invulling van het begrip bodemkwaliteit en heeft uitsluitend betrekking op het vermogen van gronden om, ondanks de aanwezigheid van pathogenen, de expressie van de pathogeen in het gewas laag te houden. Negen mechanismen waarop de ziektewerendheid gebaseerd kan zijn worden beschreven. Het feitelijk vaststellen (meten) van ziektewerendheid gebeurt in biotoetsen met specifieke plant-pathogeen combinaties. Dat is duur en tijdrovend. Daarom wordt gezocht naar afgeleide indicatoren en parameters. Resultaten uit de literatuur worden gepresenteerd. Uiteindelijk is het van belang of telers de ziektewerendheid daadwerkelijk kunnen sturen door teeltmaatregelen. Vijf (groepen van) teeltmaatregelen worden besproken. In deel 2, ziektewerendheid tegen bodemgebonden schimmels, worden zes schimmelziektes meer gedetailleerd besproken

SPECIES IDENTITY IMPORTANT TO ACHIEVE BENEFITS OF DIVERSE GRASSLAND MIXTURES

In semi-natural grasslands, plant diversity has shown to correlate with increased primary production and reduced weed invasion. If such positive effects also apply to low input agricultural grasslands, the resource-use efficiency could be improved. To investigate whether other grassland species and diverse grassland mixtures could be more productive, a grassland on a shallow sandy soil in the south of the Netherlands was sown in April 2009 with seven non-leguminous grassland mixtures. Though some sown species vanished quickly, diverse mixtures proved less susceptible for invading species three years after sowing (p<0.05). Yields in 2010 and 2011 were 11% higher for mixtures with two functional groups of grassland species compared with mixtures with only one functional group (p<0.05). A further increase in species diversity did not further increase production though overyielding was significant, transgressive overyielding was not apparent, mainly due to the strong effect of one specific functional group: mixtures containing tussock grass had a 14% higher production than mixtures without tussock grass. Tussock grass (mainly Dactylis glomerata) also had a major effect on botanical composition: Trifolium repens did invade into mixtures without tussock grass to a much higher extent (19% of the ground cover) than into mixtures with tussock grass (6%; p<0.01). However, total ground cover by invading species was mainly influenced by the number of functional groups present in the sown mixture. The results suggest that diverse grassland mixtures can improve agricultural production and reduce the susceptibility of grass sods for invading species, but that the specific composition of the mixtures has a strong influence

Mechanical ventilation with high tidal volumes attenuates myocardial dysfunction by decreasing cardiac edema in a rat model of LPS-induced peritonitis

<p>Abstract</p> <p>Background</p> <p>Injurious mechanical ventilation (MV) may augment organ injury remote from the lungs. During sepsis, myocardial dysfunction is common and increased endothelial activation and permeability can cause myocardial edema, which may, among other factors, hamper myocardial function. We investigated the effects of MV with injuriously high tidal volumes on the myocardium in an animal model of sepsis.</p> <p>Methods</p> <p>Normal rats and intraperitoneal (i.p.) lipopolysaccharide (LPS)-treated rats were ventilated with low (6 ml/kg) and high (19 ml/kg) tidal volumes (Vt) under general anesthesia. Non-ventilated animals served as controls. Mean arterial pressure (MAP), central venous pressure (CVP), cardiac output (CO) and pulmonary plateau pressure (P_plat) were measured. <it>Ex vivo </it>myocardial function was measured in isolated Langendorff-perfused hearts. Cardiac expression of endothelial vascular cell adhesion molecule (VCAM)-1 and edema were measured to evaluate endothelial inflammation and leakage.</p> <p>Results</p> <p>MAP decreased after LPS-treatment and Vt-dependently, both independent of each other and with interaction. MV Vt-dependently increased CVP and Pplat and decreased CO. LPS-induced peritonitis decreased myocardial function <it>ex vivo </it>but MV attenuated systolic dysfunction Vt-dependently. Cardiac endothelial VCAM-1 expression was increased by LPS treatment independent of MV. Cardiac edema was lowered Vt-dependently by MV, particularly after LPS, and correlated inversely with systolic myocardial function parameters <it>ex vivo</it>.</p> <p>Conclusion</p> <p>MV attenuated LPS-induced systolic myocardial dysfunction in a Vt-dependent manner. This was associated with a reduction in cardiac edema following a lower transmural coronary venous outflow pressure during LPS-induced coronary inflammation.</p

STRUCTURAL CHANGES OF THE HEART DURING SEVERE SEPSIS OR SEPTIC SHOCK

Cardiovascular dysfunction is common in severe sepsis or septic shock. Although functional alterations are often described, the elevated serum levels of cardiac proteins and autopsy findings of myocardial immune cell infiltration, edema, and damaged mitochondria suggest that structural changes to the heart during severe sepsis and septic shock may occur and may contribute to cardiac dysfunction. We explored the available literature on structural (versus functional) cardiac alterations during experimental and human endotoxemia and/or sepsis. Limited data suggest that the structural changes could be prevented, and myocardial function improved by (pre-)treatment with platelet-activating factor, cyclosporin A, glutamine, caffeine, simvastatin, or caspase inhibitors