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Económico com Lusa 

16/08/10 15:35

Portugal tem duas universidades na lista das 500 melhores do mundo, numa análise feita pela Universidade de Jiaotong, de Xangai, na China.

A Universidade de Lisboa e a Universidade do Porto são as únicas portuguesas da lista, surgindo ambas na posição 401, lado a lado com vários institutos.

O 'top 500', revelado por aquela universidade chinesa, é muito esperado na Europa, onde é também muito contestado, uma vez que, pelo oitavo ano consecutivo, o primeiro lugar é ocupado pela Universidade de Harvard, nos Estados Unidos. À semelhança da edição de 2009, os Estados Unidos ocupam 17 dos 19 primeiros lugares.

As três primeiras posições mantêm-se inalteradas, havendo apenas uma troca directa entre o segundo e o terceiro postos: Harvard em primeiro e Berkeley rouba o segundo lugar a Stanford.

Na Europa, apenas as britânicas rivais de Cambridge (5.º) e Oxford (10.º) estão entre os dez primeiros lugares. Todas as outras são norte- americanas.

Na vigésima posição, a Universidade de Tóquio é o primeiro estabelecimento não americano e não europeu a aparecer.

A Suíça, com o Instituto Tecnológico de Zurique, ocupa a 23.ª posição. O Canadá aparece em 27.º lugar, com a Universidade de Toronto, e a Bélgica surge apenas no 90.º posto, com a Universidade de Gand.

Na lista das 500 universidades, a Alemanha está a ganhar terreno, sendo o segundo país com mais estabelecimentos classificados, 39 universidades, ainda assim muito longe dos Estados Unidos, que têm 154.

O Reino Unido tem 38 universidades qualificadas e o Japão 25. Já a França, que estava em quinto lugar em 2009, com 23 universidades, desceu um lugar no ranking por países, com 22 universidades, em ex-aequo com Itália e China.

Feita desde 2003, esta classificação nasceu quando a China decidiu dotar-se de universidades de prestígio internacional. Trata-se de definir critérios para que uma universidade seja considerada de interesse mundial e de analisar o posicionamento dos institutos chineses.

Hoje, a Jiaotong parece um pouco ultrapassada pelo interesse que o seu posicionamento suscita, uma vez que esta análise está a levantar várias críticas na Europa, sobretudo em França.

A Europa - que pretende estabelecer a sua própria classificação em 2011 - defende que os critérios tidos em conta penalizam as suas universidades e que a qualificação é quase exclusivamente científica. De facto, os critérios de Jiaotong consideram essencialmente o desempenho de um instituto em matéria de investigação, não equacionando a formação.

Ou seja, é considerado o número de prémios Nobel, as medalhas Fields (equivalentes ao Nobel em Matemática) e os artigos publicados em revistas unicamente anglo-saxónicas como a Nature ou a Science, sendo excluídas as francesas.

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Today's top-end combines are at the limits in terms of width and height, but not length - an area that Massey Ferguson is clearly looking to exploit.



Providing a glimpse of what big combines could look like in 2030, this futuristic design comes from Coventry University student Henry George Parnell.

Supporting a massive 60ft (18.29m) header and offering a whopping 11.4sq m of threshing area, it has a target weight of 22t. Power comes from a 700hp engine and all eight wheels also have their own 65hp electric motors.

The 18,000-litre grain tank is located behind the articulation point. Hydraulic rams will allow operators looking for even more capacity to push out the sides by a metre. The tank then holds 24,000 litres.

Four axles help to spread the load and even though it is 12m long, the combine can still be legally driven on the road.

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Ofertas de emprego

por papinto, em 11.08.10
  • AGROEMPREGO - Ofertas de emprego para Eng Agrónomo, Agro-Industrial, Florestal, Alimentar, Zootécnico, Ambiente, Veterinário, etc. . - Envie-nos as suas ofertas, comentários, questões, sugestões, etc.

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Philip Case

Friday 06 August 2010 11:15

With next season's fertiliser prices breaking through the £200/t barrier, green manures could prove attractive this coming season. Philip Case looks at the options and how to manage them


Growing a cover crop or green manure is mainly associated with building fertility in organic systems, but the rise in fertiliser prices means that conventional growers could benefit, too.

Anton Rosenfeld, a research officer at Garden Organic, highlighted at a recent Garden Organic green manures workshop in Warwickshire that from 2003 to 2009, fertiliser prices rose by 51% in the UK. In contrast, the cost of growing green manures had risen by just 7% in the same period.

While not a new concept, conventional growers are being urged to look again at green manures as the change in economics will mean greater savings in fertiliser inputs.

The amount of nitrogen contributed by green manures depends on several factors, including weather, management, and availability of nutrients and the correct rhizobacteria in soil.

Francis Rayns, a research manager at Garden Organic, highlighted one ADAS project on a clover crop that fixed 500kg N/ha per year, but 100-300kg N/ha is more typical.

Dr Rosenfeld highlighted the potential savings in nitrogen fertiliser use, by using green manures, assuming a typical 150kg of N/ha is fixed. At 2010 prices (£220/t) this is a cost saving of £98/ha, he said. In 2009 when fertiliser prices were much higher (£368/t = £1.08 kg/N), this is a saving of £162/ha.


• Reduces nitrate leaching

• Fixes nitrogen and saves fertiliser costs

• Build up organic matter

• Help with disease and weed control

• Generate points for agri-environment schemes


• Time and money spent on crops

• May delay drilling of spring crop

• Not a priority in conventional cropping 

On top of the fertiliser saving, green manures bring a number of other benefits. They can improve soil fertility, structure and water-holding capacity, suppress weeds, stimulate microbiological life in the soil and help the environment by reducing leaching risk in winter.


The result is an improved performance in the subsequent crop and often beyond. Dr Rosenfeld pointed to one case where there was a 0.8t/ha improvement in barley yield. With potatoes, there was an extra 7.7t/ha [£121/t 2009 conventional maincrop potatoes] - a cost benefit of £932/ha.

Green manures can be grown as annual crops or just for overwintering areas or even undersown in cereal crops. But the key one highlighted by Mr Briggs is the winter crop which is incorporated prior to spring drilling, releasing the fixed nitrogen and other nutrients to the following crop.

So what green manure options are there? There are a number of crops, the key ones being black medick, white or red clover and lucerne.

However, it is important to choose the right species for the right task. Although red clover is a popular option, it can be disease prone when grown too often, so ideally a five-year break should be left between crops.

Therefore, growers should look at other species, too. To prevent overwinter leaching, grazing rye is by far the best. It establishes rapidly producing lush leaf growth and work by Garden Organic has shown that it will typically reduce leaching of nitrogen by 90% over the winter period. But it must be established early in September to be effective.

On heavy soils, Stephen Briggs, director of Abacus Organic Associates, recommended mustard or grazing rye mixed with some black medick (yellow trefoil). They are better suited to overwintered cold conditions.

Over a longer period, white clover or lucerne are the best bets. Although slower to establish, they show better persistence over a longer period than the other species. Lucerne also shows good drought tolerance on light soils.

Vetch is suited to both light and heavy soils and it fixes nitrogen well, but seed rates may need to be increased for heavier soils.

For a quick flush of nitrogen in the spring, Mr Briggs recommends red clover or black medick, because they decompose rapidly and release nitrogen quickly. Mustard, however, has a woody stem and a high carbon/nitrogen ratio and releases nitrogen later.


For autumn drilling, seeds should be sown into a good, firm seed-bed, and be rolled down well, Mr Briggs advises.

Green manures can be either drilled or broadcast. Any drill that can drill close to the surface and handle small seeds is suitable.

The depth is particularly important for clovers which are small seed and should be drilled no deeper than 1cm or emergence will be poor. Seed costs for clover, sown at a rate of 10kg/ha are typically £60/ha. Generally, green manure seeds cost £2-6/kg. Seed rates for leguminous green manures are typically 10-15kg/ha.

Green manures should be topped before incorporation then they can be ploughed or rotavated in. Spraying with a herbicide is an option for conventional farms. He also stresses that for cereal crops, it is important that they are sown soon afterwards to make use of the nitrogen released.

Looking at this season, Mr Briggs says growing manures was "challenging", due to dry conditions. But growing mustard with legumes worked particularly well, as a protection against flea beetle.

"The mustard grows faster than the legumes, and the flea beetle preferentially attacks the mustard, leaving the clover to grow underneath. "When you top the mustard off, the clover is fine below."


Fallow land

Green manures can be used to build fertility on fallow land, thereby helping growers gain extra points under agri-environment schemes, says Mr Briggs.

Under ELS, sowing red clover or white clover as winter cover crops pffer 65 points/ha, helping growers meet the requirements of the Campaign for the Farmed Environment (CFE).

Alternatively, growers with severe blackgrass problems looking to fallow badly affected areas could put some overwintered green manure in to protect the soil and provide some nitrogen.

Undersowing a standing crop and keeping it in over winter can be an even better option, says Mr Briggs. "It will help with your blackgrass problem, reduce your fertiliser bill and improve soil structure."


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Calendário escolar 2010/2011

por papinto, em 02.08.10

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