Distribució del gènere "Arthrinium" a Catalunya

An account is made of the distribution of this fungus genus in some natural substrates from Catalonia

Distribució del gènere "Arthrinium" a Catalunya

An account is made of the distribution of this fungus genus in some natural substrates from Catalonia

Modelling the growth and utilisation of kikuyu grass (Pennisetum clandestinum) under grazing. 1. Model definition and parameterisation

This paper describes a Tropical Pasture Simulator. This is a simple mechanistic model representing the growth of vegetative tropical pastures under rotational or continuous grazing with responses to N fertiliser, temperature and irradiance that can be used as a tool to study management options for the development of sustainable grazing systems. The model was derived as an adaptation of the `Hurley pasture models' which were originally designed to simulate the growth of ryegrass. The model incorporates the processes of light interception and photosynthesis, leaf area expansion; growth, ageing and senescence of plant tissues, recycling of substrates from senescing tissues, nitrogen uptake, mineralisation of soil organic N, N leaching and grazing. The paper discusses the main structure of the model, its components and the main adaptations required to simulate the growth of tropical pastures. The model was parameterised for kikuyu grass (Pennisetum clandestinum) growing in dairy systems in highland regions of Costa Rica. This paper also discusses the sensitivity of parameter values and the development of minimum parameter datasets for time and cost-effective implementation of the model

A integração socio-bio-econômica através de modelos matemáticos: uma aplicação de estudo na região sudeste do Estado do Rio Grande do Sul - Brasil.

O campo nativo pastejado por bovinos e ovinos é uma das principais características da região sudoeste do Rio Grande do Sul. A área ocupada por pastagem cultivada ainda é muito restrita na região, tendo geralmente o trevo branco (Trifolium repens L.), cornichão (Lotus corniculatus L.) e o azevém anual (Lolium multiflorum L.) como seus principais componentes.bitstream/item/64709/1/bpd22.pd

Achieving grassland production and quality that matches animal needs

Permanent grasslands are exploited by grazing animals or as meadows depending on differentconstraints. Grazing is the most common use in large parts of Europe, especially in the northwest ofEurope. However, certain areas are less suitable for grazing. In the Alps e.g. meadows are the mostrelevant grassland utilization option because of the steepness of the terrain and a short favourableseason, so animals use stored forage during the long winter period. In the Cantabrian fringe, althoughclimate and topography allows for a long grazing season, this is practiced in few farms due to thesmall size and dispersion of parcels, making it very difficult to organise a reasonable grazing scheme.In several countries in the North West of Europe zero-grazing is practised due to different reasons likelarge herds or use of Automated Milking Systems (AMS).Permanent grasslands are highly variable. They differ markedly in their botanical composition andproductivity, ranging from agricultural-improved grasslands with few very productive plant species, tonatural and semi-natural grasslands (Peeters et al., 2014), found in a high variety of ecologicalconditions and thus with a high number of potentially dominant plant species, mostly of lowproductivity. Most ruminant livestock farmers have some agricultural-improved grassland, butdepending on the livestock system, this will be the majority of their farmland (e.g. dairy farms) or theminority (e.g. goats for meat in mountain areas).For every grassland based livestock farm, irrespective of the types of grassland used, the ideal targetis that its own forage allowance matches animal needs. These two variables –forage allowance andfeed requirements- are mainly dependent on the stable components of the farm (animals: type,number and annual and seasonal productivity (milk and/or meat); and grasslands: type, area,botanical composition, annual and seasonal productivity, nutritive quality), but also on the weather.Normally, the stable components of the farm are adapted to the climate, soils and other userestrictions of the area. It is the changeable inter-annual weather conditions that lead to variability inthe quantity and quality of available forage, and so weather conditions are the main factor affectingthe forage allowance, and so the profitability of the system in the short-medium term. The farmershave to adjust their management (fertilisation, timing of grazing / cutting, etc.) to these changeableweather conditions.Farmers feel the need to control this short-term variability generated by changing weather conditions.Staying in control is a big issue for the farmers and they feel unsure about their livestock andgrassland management if external factors like weather affect the functioning of their system. Whenthey are not in control, it is difficult for them to see the economic profits of certain improvements,such as grazing instead of cutting in dairy or beef cattle systems (Peyraud et al, 2010).Aim o

Integración de trabajos de investigación para la gestión sostenible de los pastos de montaña del Norte peninsular

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