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Food for thought

Climate change, a rising population and the need to produce “more for less” have put a lot of pressure on the food industry in countries all around the world.  Scientists at SCRI, the Scottish Crop Research Institute, may have some of the answers but as well as satisfying the increasing public appetite, they also have to satisfy public opinion – and balance the demand for cheap and plentiful food, environmental protection and profits... …

Food for thought

Article by Peter Barr

Farmers today are expected to do more than ever – producing cheaper, better-quality, 'greener' and more plentiful food, using fewer resources.  They are also expected to be caretakers of the rural environment, minimising pollution (using fewer pesticides and reducing carbon dioxide emissions) at the same time as ensuring greater biodiversity and providing open access to the countryside for leisure. 

Environmental pressure groups, businesses and scientists all have their different ideas about how to deal with these issues.  And for Professor Peter Gregory, SCRI’s Chief Executive, a 'greener future' will depend on three strategic objectives:

1. durable disease resistance (increase crop yield by reducing the damage caused by common diseases and pests)
2. better use of resources – e.g. nutrients and fertilisers, energy and water
3. increase food production at the same time as ensuring long-term sustainability (reducing carbon footprint & protecting biodiversity)

The arithmetic is simple.  Over the last 60 years, food production has improved dramatically, with yields for major crops like barley and potatoes increasing by two to three times per hectare.  For example, we now produce about 45 tonnes of potatoes per hectare compared to roughly 14-15 tonnes in 1950.  Since then, however, the world's population has also more than doubled – from roughly three billion to much more than six billion people.  According to United Nations figures, population will increase by a further 50 per cent by the year 2050, with demand for food and energy almost doubling because of changes to diet.  And to meet demand, farmers and scientists need to cut wastage and improve efficiency, on less land with fewer resources, under greater political pressure than ever before.

In addition to survival of the planet, agriculture also makes a major economic contribution to society.  In Scotland, for example, barley is the largest arable crop, producing 700,000 tonnes on 300,000 hectares, most of it for whisky, which alone earns more than £3 billion-worth of exports a year, generates £800 million in taxes and employs about 65,000 people.  The world's third-largest crop – potatoes – is worth over £3 billion a year and 15 per cent of the crop is destroyed by disease every year – including late blight, which accounts for 25 per cent of losses.  About £100 million is spent on pesticides to stop this, and the losses would increase from £55 million a year to an estimated £360 million if pesticides were not used. 

Faced with all these issues, scientists think that a mix of solutions is what is required, including the latest genetic techniques.  In recent years, progress has come from a number of different advances including breeding new varieties of plants.  As well as using more robust and productive varieties, farmers have also sprayed a variety of chemicals on crops to fight pests and common diseases.  In the future, however, genetics will play a bigger role in agricultural advances, combined with better land use and new, less toxic biological products.  Gregory believes that better use of genetic techniques – for example, introducing the genes which control many deadly diseases – could accelerate progress in a number of ways, producing new disease-resistant plants in five to 10 years, compared to 25-30 years using conventional methods. 

Like other research teams in the UK, SCRI is allowed to use genetic engineering techniques and grow new varieties under controlled conditions, but is not permitted to grow these new crops out of doors – unlike researchers in the USA, South America and China.  Many scientists believe that this is limiting progress and may, in time, damage the country's agricultural sector. 

For two to three decades, researchers have been introducing genes from more exotic varieties – for example, from the phureja potato which has resistance to several diseases – and even though this may lead to a narrower range of plants because they offer better returns on investment, it also means greater diversity within the range. 

Gregory believes that genetic research is crucial to the future of world food production – and that  publicly funded organisations like SCRI have a key role to play to make sure we make rapid progress at the same time as striking a balance between greater productivity and the longer-term issues that concern our society.  “It's important new technologies are developed by public research institutions, for the public good,” he says.  “Otherwise, the new technologies will go to private enterprise, where there may be a conflict of interests – for example, if the same company involved in food production also sells pesticides.  We work very closely with the private sector (for example, breeding different varieties, increasing yields and improving taste) but we also focus on key public issues like long-term sustainability, biodiversity, reducing pollution and the carbon economy – not only profits.” 

In Gregory's opinion, we also need “an open research climate” for genetics so the benefits are shared by everyone and scientists can access the results of research for the sake of the world as a whole.  As part of this effort, SCRI works at the forefront of international genome sequence research – one of the leaders in barley and soft fruit and a significant contributor to genome research for potatoes. 

To study the pathology of different diseases and understand the genetics involved, SCRI scientists first search for clues on how they overcome a plant's defences.  When they understand the process and the chemicals plants use to fight the attackers, they can start to work out how to prevent it.  For example, says Gregory, researchers are now beginning to understand how late blight “invades the cells” of potatoes, and have identified the protein which appears to be to blame – the same protein involved in malaria.   With black leg, “an organism which smashes the cell walls of plants,” the pathogen responsible has many features in common with bacteria found in the human gut.  SCRI also does a lot of research into soft fruits and barley, and is making rapid progress with diseases like rhynchosporium – a fungus which can reduce barley yield by up to 40 per cent, and like many other diseases is hard to detect until is too late to stop it.  If we could eliminate these common diseases, we could reduce wastage in some crops by 30 per cent, but Gregory reveals that the problem is also more complex than scientists used to believe.  “In the past,” he explains, “we tended to look for the major gene that controls the disease, but now we understand we can't rely on one single gene but a network of genes.”

Advances in bioinformatics have made a huge difference to genetic research, and even in the last two years have led to rapid progress in our understanding of common diseases like black leg and blight.  For example, using the latest computing techniques, scientists at SCRI recently discovered that black leg causes damage long before the disease starts smashing the cell walls of plants.  Researchers before then were “asking the wrong question” of the disease and are now in a better position to identify the source of the problem and do something about it. 

Genetic breakthroughs and the fight against disease may grab the headlines, but in recent years, SCRI has stepped up its efforts across the whole spectrum of research, particularly biodiversity and better land use, as well as better use of nutrients (e.g. nitrogen and phosphorus) and water.  Reducing wastage caused by disease is important but so too is the search for new alternatives for fertilisers, pesticides and chemicals.  On the one hand, there's a need to reduce the amount of pollutants which end up in the water supply, and on the other there's a projected shortage of ingredients like phosphates, which come from rapidly diminishing guano reserves.  Gregory also emphasises the need to “use scarce resources wisely and help plants use nutrients as efficiently as possible.”  Since 70-80 per cent of the world's total fresh water supply is channelled into agriculture, water management is also essential – for example, ensuring clean water and developing crops which better utilise water, as well as drought-resistant crops and better soil management. 

The 'carbon economy' is also important to SCRI, and this means looking at the way we use 'high carbon cost' ingredients like nitrogen, as well as helping to develop new solutions like biochar and using agricultural land to store carbon.

Farmers and scientists often use the expression “plough to plate” but Gregory uses the more down-to-earth “seed to sewage” to describe the agricultural cycle and the work of SCRI.   And when it comes to the environment and current crop production methods used around the world, which can be highly wasteful, uneconomic and also unhealthy, he asks: “Is this a sensible way to run a business?”

SCRI, which is based in Invergowrie on the outskirts of Dundee, recently launched a new project at Balruddery Farm in nearby Angus, as part of its initiative to conduct research on nutrients and water – with an emphasis on sustainability and the long-term impact of climate change.  The primary aim is improved arable biodiversity, greater crop resilience and productivity, and “yield stability” at levels which would satisfy commercial requirements. The project will gather data over at least four rotation cycles, over a period of more than 20 years.  To achieve this, SCRI will design “a sustainable cropping system based on existing research to optimise inputs, yield, biodiversity and ecosystem processes.”

Even if scientists develop a new strain which greatly increases the yield, the big question is can this be sustained over the long term?  At Balruddery, the researchers are investigating what could be described as 'crop rotation plus' – looking at the long-term effects of rotating different crops and new varieties not just in terms of basic yield but also overall sustainability, the health of the soil and the general environment.  It's no good boosting yield by 100 per cent if this destroys the soil or chases the wildlife away, leading to more problems down the line.  So, long-term observation is required.  Similarly, if we develop new disease-resistant crops using genetic techniques, it will still take a few years to test them for longer-term, knock-on effects. 

The Balruddery “experiment” is a miniature agricultural system, and Gregory hopes it will teach us to rethink not just the biology of farming but also the geography.  Can we do everything in the same place – balancing our drive to increase production with the need to protect the environment?  Or will we have to separate activities, maintaining some places for farming and others for biodiversity and recreation? 

As well as what it does at home, SCRI also helps producers all over the world – for example, developing new virus-free seed potatoes for growers in Kenya and Malawi.  In Africa, says Gregory, the critical issue is not just climate change but climate variation, with periods of “feast and famine” posing major long-term planning problems for farmers.  In Australia, for example, where Gregory worked for a number of years, farmers keep a range of four or five varieties of wheat crops, to cope with different climate conditions.

For Gregory, the biggest challenge farmers face today is how to strike a balance between competing interests and reach a compromise between increased production, land use and environmental issues.  “What are the trade-offs?” he asks.  “Very often, 'green' crops are equated with organic, but if this means reducing yield by 25 per cent, it means we need 25 per cent more land for growing the crop.  Organic may be greener in some ways, but conventional systems can also be green.”

The 'green agenda' raises many critical questions, but Gregory suggests that although many people believe there is one simple answer, the science is much more complex. 















"Food for thought". Science Scotland (Issue Nine)
Printed from on 03/04/20 12:11:26 PM

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