Soil biota in grassland, its ecosystem services and the impact of management

In the search for sustainable grassland systems, self-regulating processes in the soil become increasingly important. Soil biota play an important role in these processes and in the provision of various ecosystem services. For grassland systems important ecosystem services are supply of nutrients, soil structure maintenance and water retention. For developing and optimising sustainable grassland systems, insight is needed into the mechanisms by which soil biota are influenced by management and what it means for the functioning of the soil-plant system. Interactions between soil and plants can be represented by a cyclic conceptual framework including plant/roots, soil biota and soil properties. The challenge for sustainable grassland is to allow this cycle to function optimally with a minimum of external inputs. In these systems the soil food web is probably bacterial-based with a high density of earthworms. The impacts of grassland management on soil biota are discussed on the basis of two cases: use of grass-clover mixtures and a ley-arable crop rotation versus permanent grassland and continuous arable land

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

Women in Science, Technology, Engineering, and Mathematics (STEM): An Investigation of Their Implicit Gender Stereotypes and Stereotypes' Connectedness to Math Performance

In spite of many barriers facing women's enrollment in Science, Technology, Engineering, and Mathematics (STEM), some women are successful in these counter-stereotypic disciplines. The present research extended work primarily conducted in the United States by investigating implicit gender-STEM stereotypes—and their relation to performance—among female and male engineering and humanities students in Southern France. In study 1 (N = 55), we tested whether implicit gender-math stereotypes—as measured by the Implicit Association Test (IAT; Greenwald et al. 1998)—would be weaker among female engineering students as compared to female humanities, male engineering and male humanities students. In study 2 (N = 201), we tested whether this same results pattern would be observed with implicit gender-reasoning stereotypes (using a newly created IAT) and, in addition, whether implicit gender-reasoning stereotypes would be more strongly (and negatively) related to math grades for female humanities students as compared to the three other groups. Results showed that female engineering students held weaker implicit gender-math and gender-reasoning stereotypes than female humanities, male engineering and male humanities students. Moreover, implicit stereotyping was more negatively related to math grades for female humanities students than for the three other groups. Together, findings demonstrate that female engineering students hold weaker implicit gender-STEM stereotypes than other groups of students and, in addition, that these stereotypes are not necessarily negatively associated with math performance for all women. Discussion emphasizes how the present research helps refine previous findings and their importance for women's experience in STE

Biologische boer als natuurbeheerder

Naast landbouwgronden kent Nederland ook natuurgronden zoals gras- en rietlanden en reservaatakkers. Beheerslanden die regelmatig worden gemaaid vragen extra kosten voor het afvoeren van plantenresten. Samenwerking met boeren is dan interessant. Dit vraagt echter om een goede landelijke regeling waarbij de kosten in redelijkheid worden verdeeldBiologische boeren kunnen hieraan een bijdrage leveren, maar is dit wel interessant en rendabel? Het Louis Bolk Instituut doet onderzoek naar rendabele en werkzame systemen om beheersgronden tot een wederzijdse meerwaarde te brengen voor boeren en natuurorganisaties

Improved estimation of starting times of human activities using Hidden Markov modeling based activity classification?

Automated classification of human activities should help the researcher, or the physician, with the interpretation of data. In a previous study a novel activity classifier based on Hidden Markov Models was successfully implemented and tested on ambulatory obtained of human activities. The estimated starting times were not accurate. Here the addition of timing information to perform isolated activity training as initialization of the HMM's is proposed to more accurately estimate the starting times of activities

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

Analysis of the soil food web structure under grass and grassclover

The below ground biodiversity of soil organisms plays an important role in the functioning of the the soil ecosystem, and consequently the above ground plant production. The objective of this study is to investigate the effect of grass or grass-clover in combination with fertilisation on the soil food web structure. In 2003 a fertilisation trial on grass and grassclover was sampled for soil organisms. Data were agglomerated in seven trophic groups, and classified by means of TWINSPAN. TWINSPAN clearly distinguished three main soil food web structures: Type 1: Grass plots with a high biomass of bacteria and fungi; Type 2: Grass-clover plots with a high biomass of earthworms; Type 3: Grass and grass-clover plots, that received relativily high fertilisation, with a high number of nematodes. Results suggest a microbial oriented soil food web for grass and an earthworm orientated soil food web for grass-clover