PRIONS in our beef. Insecticides on our grapes. Nitrates in our rivers. Modified genes in our corn. What next? Never has the food on our plates seemed so heavily sauced with worry. At the same time, the signs of much deeper problems are all around. Agricultural test plots – once ranked among the most boring bits of the rural landscape – are now the scenes of pitched battles between agribusiness giants and the opponents of genetically modified crops. Meanwhile, British farmers are quitting in droves, especially after last year’s outbreak of foot and mouth disease.
Most ominously, the world’s population continues to climb. And despite the rise of high-tech agriculture, 800 million people don’t get enough to eat. Admittedly, that’s often due to a lack of money – the world actually produces enough for everyone, at least for now. But by 2050 we will have 9 billion mouths to feed, 3 billion more than today. Finding food for all those people will tax farmers’ – and researchers’ – ingenuity to the limit. Yet already, precious aquifers that provide irrigation water for some of the world’s most productive farmlands are drying up or filling with seawater, and arable land in China is eroding to create vast dust storms that redden sunsets as far away as North America.
Clearly it’s time to rethink the food we eat and where it comes from. Feeding 9 billion people will take more than the same old farming practices, especially if we want to do it without felling rainforests and planting every last scrap of prairie. “Agriculture must become the solution to environmental problems in 50 years. If we don’t have systems that make the environment better – not just hold the fort – then we’re in trouble,” says Kenneth Cassman, an agronomist at the University of Nebraska at Lincoln. That view was echoed in January by the Curry report, a government panel that surveyed the future of farming and food in Britain.
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It’s easy to say agriculture has to do better, but what should this friendly farming of the future look like? Concerned consumers come up short at this point, facing what appears to be an ever-widening ideological divide. In one corner are the techno-optimists who put their faith in genetically modified crops, improved agrochemicals and computer-enhanced machinery; in the other are advocates of organic farming, who reject artificial chemicals and embrace back-to-nature techniques such as composting. Both sides cite plausible science to back their claims to the moral high ground, and both bring enough passion to the debate for many people to come away thinking we’re faced with a stark choice between two mutually incompatible options.
Not so. If you take off the ideological blinkers and simply ask how the world can produce the food it needs with the least environmental cost, a new middle way opens. The key is sustainability: whatever we do must not destroy the capital of soil and water we need to keep on producing. Like today’s organic farming, the intelligent farming of the future should pay much more attention to the health of its soil and the ecosystem it’s part of. But intelligent farming should also make shrewd and locally appropriate use of chemical fertilisers and pesticides. The most crucial ingredient in this new style of agriculture is not chemicals but information about what’s happening in each field and how to respond. Yet ironically, this key element may be the most neglected today.
Clearly, organic farming has all the warm, fuzzy sentiment on its side. An approach that eschews synthetic chemicals surely runs no risk of poisoning land and water. And its emphasis on building up natural ecosystems seems to be good for everyone. Perhaps these easy assumptions explain why sales of organic food across Europe are increasing by at least 50 per cent per year.
Going organic sounds idyllic – but it’s naive, too. Organic agriculture has its own suite of environmental costs, which can be worse than those of conventional farming, especially if it were to become the world norm. But more fundamentally, the organic-versus-chemical debate focuses on the wrong question. The issue isn’t what you put into a farm, but what you get out of it, both in terms of crop yields and pollutants, and what condition the farm is in when you’re done.
Take chemical fertilisers, which deliver nitrogen, an essential plant nutrient, to crops along with some phosphorus and potassium. It is a mantra of organic farming that these fertilisers are unwholesome, and plant nutrients must come from natural sources. But in fact, the main environmental damage done by chemical fertilisers as opposed to any other kind is through greenhouse gases – carbon dioxide from the fossil fuels used in their synthesis and nitrogen oxides released by their degradation. Excess nitrogen from chemical fertilisers can pollute groundwater, but so can excess nitrogen from organic manures.
On the other hand, relying solely on chemical fertilisers to provide soil nutrients without doing other things to build healthy soil is damaging. Organic farmers don’t use chemical fertilisers, so they are very good at building soil fertility by working crop residues and manure into the soil, rotating grain with legumes that fix atmospheric nitrogen, and other techniques.
This generates vital soil nutrients and also creates a soil that is richer in organic matter, so it retains nutrients better and is hospitable to the crop’s roots and creatures such as earthworms that help maintain soil fertility. Such soil also holds water better and therefore makes more efficient use of both rainfall and irrigation water. And organic matter ties up CO2 in the soil, helping to offset emissions from burning fossil fuels and reduce global warming.
Advocates of organic farming like to point out that fields managed in this way can produce yields just as high as fields juiced up with synthetic fertilisers. For example, Bill Liebhardt, research manager at the Rodale Institute in Kutztown, Pennsylvania, recently compiled the results of such comparisons for corn, wheat, soybeans and tomatoes in the US and found that the organic fields averaged between 94 and 100 per cent of the yields of nearby conventional crops.
But this optimistic picture tells only half the story. Farmers can’t grow such crops every year if they want to maintain or build soil nutrients without synthetic fertilisers. They need to alternate with soil-building crops such as pasture grasses and legumes such as alfalfa. So in the long term, the yield of staple grains such as wheat, rice and corn must go down. This is the biggest cost of organic farming. Vaclav Smil of the University of Manitoba in Winnipeg, Canada, estimates that if farmers worldwide gave up the 80 million tonnes of synthetic fertiliser they now use each year, total grain production would fall by at least half. Either farmers would have to double the amount of land they cultivate – at catastrophic cost to natural habitats – or billions of people would starve.
In short, the world needs chemical fertilisers – even though farmers in much of the temperate zone produce so much grain that they are hard-pressed to sell it at a profit. But if they were to cut back drastically on their fertiliser use and harvests were to shrink, grain prices would go up all over the world, making poor people hungrier. Besides the obvious moral cost of that, there is an environmental one: nothing destroys ecosystems more surely than poor, hungry people who can’t afford to think about tomorrow because they’re desperate to feed their kids today.
That doesn’t mean farmers couldn’t get by with less fertiliser. Technologically advanced farmers in wealthy countries, for instance, can now monitor their yields hectare by hectare, or even more finely, throughout a huge field. They can then target their fertiliser to the parts of the field where it will do the most good, instead of responding to average conditions. This increases yield and decreases fertiliser use. Eventually, farmers may incorporate long-term weather forecasts into their planning as well, so that they can cut back on fertiliser use when the weather is likely to make harvests poor anyway, says Ron Olson, an agronomist with Cargill Fertilizer in Tampa, Florida.
The solutions are different in the world’s least developed areas, including most of Africa, which have been bypassed by the Green Revolution. Poor roads and railways mean that synthetic fertilisers often cost up to five times as much as the world price, putting them far out of reach for most farmers. As a result, African farmers apply just 12 kilograms of fertiliser per hectare, on average-far less than the 40 kilograms of nutrients they remove with each year’s harvest. “You’ve got some real soil mining going on,” says Peter Hazell, an economist at the International Food Policy Research Institute in Washington DC. “In those kinds of environments, to talk about not using fertiliser just doesn’t make any sense at all. More fertiliser is going to help the environment.”
Most of these farmers will use “organic” methods of enriching the soil, because that’s all they can afford. But with a little training in improved techniques they can often boost their soil quality – and their yields – dramatically. For example, Nigerian farmers who add even one or two animals to their holdings can use the manure to enrich their soil. This, plus growing nitrogen-fixing legumes, can increase yields by 100 per cent or more almost immediately (91av, 27 October 2001, p 44).
Another way to boost yields, and enjoy environmental benefits, is to combine several crops on a single patch of ground. A mixture of crop species does a better job of capturing light and other resources than any single crop, and it is also better at keeping down weeds and insect pests. In Mexico, for example, a mixed planting of maize, squash and beans produces 1.7 times as much food per hectare as maize monoculture, according to studies by Miguel Altieri of the University of California at Berkeley. In addition, it produces twice as much straw for ploughing into the soils to maintain nutrient levels.
Intercrops of this sort are difficult to tend and harvest by machine, which has restricted their use mostly to the smallest farms – one reason why small farms all over the world tend to produce better yields than larger ones. But even mechanised farmers may be able to adapt some of these techniques, for instance by alternating strips of two or three different crops. The US National Center for Appropriate Technology reports that when a farmer in Iowa mixed oats and soybeans with his corn in this way, corn yields rose by 25 per cent and oat yields by 9 per cent, while soybean yields declined only slightly compared with monoculture.
Organic techniques certainly have their benefits, especially for poor farmers. But strict “organic agriculture”, which prohibits certain technologies and allows others, isn’t always better for the environment. Take herbicides, for example. These can leach into waterways and poison both wildlife and people. Just last month, researchers led by Tyrone Hayes at the University of California at Berkeley found that even low concentrations of atrazine, the most commonly used weedkiller in the US, can prevent frog tadpoles from developing properly (Proceedings of the National Academy of Sciences, vol 99, p 5476).
But if farmers were to give up using herbicides, they would lean more heavily on something that may cause even more environmental damage – the plough. Though it has become the very symbol of agriculture, ploughing is not always needed to prepare the soil for seeds or allow crops to grow. Farmers use it mostly to control weeds by burying their seeds too deep for them to emerge. It also helps air penetrate the root zone of wet clay soils and prevent waterlogging. But if farmers control weeds in other ways, most years they can abandon ploughing on most soils.
There are good reasons to do so. Repeated ploughing makes soil less springy. So tractors, which have tripled in weight in Europe and North America since 1970, compact the deep layers of soil and reduce yields. Water also runs off compacted soils more easily, increasing erosion. Experiments by Rainer Horn of Kiel University in Germany show that when farmers cut back on ploughing, they reduce this damage by a third, and the land needs less fertiliser, too.
Such “no-till” farmers can control weeds using low-growing cover crops, including nitrogen-fixing legumes such as vetch, the residues of which add organic material to the soil. Indeed, experiments in Kentucky showed that no-till maize fields fixed 40 per cent more carbon from the atmosphere into the soil than conventional fields.
No-till won’t work for wet clay soils that need aeration and vegetable crops that require more aggressive weed suppression. But where it does work, it brings a knock-on benefit for farmers that is often disregarded by environmentalists: lower costs. Appeals to environmental sustainability may or may not get farmers using a new technique, but boosting their profits will.
As a result, no-till farming has become big business in the US, where ploughing has been reduced or stopped on 35 per cent of arable land in the past decade. The shift has largely paralleled an increase in the use of maize and soybeans genetically modified to survive glyphosate, the herbicide sold as Roundup. Farmers who plant glyphosate-resistant crops can control weeds with a single spraying of this relatively benign weedkiller, rather than turning to more toxic alternatives. Even Jules Pretty of Essex University, a strong supporter of sustainable farming methods, says that a single dose of glyphosate probably does less environmental damage than ploughing. Europe’s antipathy to genetically engineered crops, however, has prevented most farmers from adopting no-till on northern Europe’s over-ploughed farmlands.
In all these systems, something has to fill the weed-control gap left by abandoning the plough. Sometimes it is covering the soil with mulch or other plants between crops, sometimes manual or mechanical weeding – although all these can have environmental impacts of their own. Many farmers can probably reduce herbicide use, but in most places herbicides are here to stay.
What about insecticides, the other main class of agrochemicals? Here, more than a decade of experience has shown that farmers need not spend money on costly insecticides when nature, if given the right sort of encouragement, can often control insect pests for free. For example, in the 1980s farmers in Asia’s high-yielding, Green Revolution rice regions noticed that the brown plant hopper, an important pest, actually got more abundant after pesticide spraying, because the sprays killed the plant hopper’s predators more efficiently than they killed the pest itself. In 1986, Indonesian rice farmers began waiting to spray until plant hopper densities rose above a critical threshold. The rest of the time they relied on the now abundant spiders and other predators to keep them in check. Since 1990, insecticide use has fallen 80 per cent, yields have risen 25 per cent, and farmers have become $1 billion richer.
This approach, called integrated pest management (IPM), works in developed countries, too. Just a few years ago, vegetable farmers in Queensland found they had to spray every second day to keep insects from devouring their crops. Desperate, they stopped spraying, started bringing back the plants, insects and birds that kept pests in check, and reduced the size of their fields to allow wildlife to penetrate the cropped area. Their yields have recovered, there are no pesticide residues on crops, and farmers have shed the expense of the chemicals.
Besides taking measures to encourage beneficial insects and birds, savvy farmers can now call on a growing repertoire of techniques such as scent traps to interfere with mate-finding or to lure insect pests away from the crop. “The technology has been there for 30 years, and it’s been successful sporadically for certain pests. But the economics of pest management are changing. I really believe in the next 10 years we’re going to see a lot more widespread use,” says Frank Zalom, an IPM specialist at the University of California at Davis. Farmers may even be able to spray their crops not with toxins but with chemical signals that put the plants’ own innate defences against pests or diseases on high alert (91av, 1 September 2001, p 36).
But there’s good reason for farmers to keep insecticides in their armoury. “There are times when ecological methods cannot adequately control pests and you do get a major outbreak,” says Hazell. At such times, adhering to strict organic guidelines may mean losing a whole crop. Even staunch organic advocates admit that many farmers won’t be able to wean themselves off insecticides – at least not yet. “If the farming system is done right, I think we won’t have to use those materials,” says Liebhardt. “It’s a worthy goal, and a lot of farmers do it. But there are a lot of farmers who can’t do that at present.”
For now, Zalom suggests that one way to reduce insecticide use – and its attendant risks of ecological damage and accidental poisoning – may be to require farmers to get a prescription from a licensed pest-control expert before they use the more toxic pesticides. That would ensure that farmers have exhausted their gentler pest-control options before they turn to poisons.
The real lesson from IPM is one that all farmers should bear in mind: the best solutions are likely to be local ones that address the peculiar mix of conditions at a particular place and time. A one-size-fits-all approach to farming – whether the rigid application of organic standards or an insistence on large-scale, high-input cropping – is almost certainly a bad approach. The world needs a supple, adaptable, intelligent approach to growing food, one in which the key inputs are brains, experience and information.
But if farmers are to have reliable, up-to-date information about what’s happening in their fields and how best to respond to it, they need ready access to expert advice. Unfortunately, in many places such information is getting harder to come by. Research into “sustainable” techniques has been growing, but remains a drop in the bucket compared with what’s spent on conventional farming. Governments have been cutting back on the money they spend on agricultural research, so most funding comes from private corporations – nearly all of them companies that also sell fertiliser, pesticides, and the patented crop varieties designed to respond to them.
At the same time, funding has been dwindling worldwide for extension agents – the trained, government-sponsored advisers who bring new techniques to the field and get farmers to try them. Now the only technological advice a farmer may get is from the representative of an agribusiness giant such as Europe’s AgrEvo or Syngenta. Often, these reps give excellent advice – but they are unlikely to push farmers toward abandoning their products. Non-profit development agencies can help fill the gap, especially in the poorest regions such as semi-arid Africa, but they too don’t have enough staff to go around, says Hazell.
So the challenge in moving toward a new, more intelligent farming of the future is as much political as it is technological. We already know ways to build better soils with less fertiliser and how to keep pests in check while spraying less. We already know how to recognise when synthetic chemicals really do provide the decisive edge farmers need to get the most out of their land. What’s missing is political will. The time has come to step out past the tired battle lines drawn up between organics advocates and agribusiness and enter the uncomfortable no-man’s-land in between where the real solutions lie.
Drop by drop
For many of the world’s crucial arable lands, the availability of water is the single greatest threat to yields. With overeager irrigators pumping many aquifers dry and causing salt build-up on huge tracts of land, the future looks especially grim. The only option is to squeeze more nutritional value out of each drop, says Sandra Postel, director of the Global Water Policy Project in Amherst, Massachusetts.
One way to do that is to waste less. Drip irrigation, for example, delivers water direct to the plant roots rather than drenching the whole field using conventional methods such as flood irrigation. This, when combined with other technologies such as soil moisture monitoring, ensures that up to 95 per cent of the water gets to the crop and boosts productivity by between 20 and 90 per cent over conventional irrigation. But drip systems are expensive, so they’re used mostly in wealthy countries to grow high-value crops like vegetables and fruit.
A simpler way to save water is to eat less meat. Livestock convert large amounts of plant material into smaller amounts of meat, so each calorie of meat takes far more water to produce than a calorie of grain (see Graphic). That’s especially wasteful in areas such as Australia and California, where much of the feed eaten by livestock comes from irrigated fields.FIG-mg23434601.jpg
Minor changes could improve the efficiency of many of the world’s largest irrigation systems, says irrigation engineer Hector Malano, director of the International Technologies Centre at Melbourne University. In many cases, simply replacing certain sluice gates with weirs, making it easier to control water flow, would save huge amounts of water.
Another technique overlooked by the Green Revolution is water harvesting – building catchments to channel sporadic rainfall from large expanses of arid land into reservoirs and then onto fields. That ancient technique made Libya the breadbasket of the Roman Empire under climatic conditions similar to today’s, and it is now allowing farmers in Rajasthan in western India to double output by harvesting two crops a year instead of one.
For many of the world’s poorest farmers, though, the problem is finding a way to tap into water supplies that are already there. “The irrigation age has entirely bypassed the small, poor farmers of 2 hectares or less,” says Postel. Simple foot-operated pumps can provide such farmers with the water they so desperately need. International Development Enterprises, a non-profit organisation based in Denver, has helped introduce 1.3 million such pumps to Bangladesh alone.
Meanwhile, agricultural researchers around the world are working to develop strains of rice and other crops that produce high yields with less water. But the task may take far more money and effort than governments are devoting to it. “We need a quantum shift in the amount of carbohydrate we can produce per unit of water,” says Wayne Meyer of the Adelaide-based Land and Water division of the CSIRO, Australia’s national research organisation. “It’s got to be seen as the equivalent of putting a man on the Moon.”
Keeping it local
It’s true what they say: buying locally grown food really does offer big advantages, not just in freshness, but also in environmental savings. Imported foods, especially those flown in from the opposite hemisphere, gobble huge amounts of jet fuel – 127 calories of fuel per calorie of Californian lettuce flown to Britain, and 66 calories of fuel per calorie of South African carrot, according to estimates by Sustain, a green research group based in London.
Much of that cost is hidden from consumers, because air fuel attracts no tax – an advantage guaranteed by international treaty. And under the Kyoto Protocol, carbon emissions from international transport aren’t added to national carbon-emission tallies, because nobody can agree whose account to charge them to. But the fuel used to import food and drink to Britain accounts for 4 million tonnes of CO2 emissions, about 2.5 per cent of the national total.
“Climate change is such an important issue that in general I think anything that can be grown or raised locally should be bought in preference to imports, even if the imports are organically produced,” says Jules Pretty of Essex University, usually a strong advocate of organic food. That’s an important lesson for shoppers accustomed to reaching for the organic produce because they think it’s kinder to the environment. In Britain, only 25 per cent of organic food is grown domestically, compared with 70 per cent of conventional food.
It’s easy to recommend buying local, but in the dead of a northern winter, most local fresh vegetables are likely to come from a greenhouse. The energy needed to heat and light a greenhouse offsets much – though probably not all – of the environmental savings from buying local. In the winter months, buying frozen, locally grown vegetables may be the soundest solution, says Pretty.
Let them eat grass
By 2020, total meat consumption in developing countries is predicted to have more than doubled. Yet livestock, especially in wealthy countries, already munches its way through 36 per cent of the world’s grain harvest. All that grain exacts a heavy environmental cost, because the increased demand pulls farmers towards growing maize and soybean and away from pasture and fodder crops such as alfalfa that do so much for soil health. And grain-fed animals tend to be housed in huge feedlots, where crowding causes disease and vets use more antibiotics, and where vast mountains of manure pollute the surroundings.
Consumers could reverse many of these problems by demanding meat from grass-fed livestock, or simply by eating less meat. And as an added bonus for overfed Westerners, the meat from grass-fed cattle is leaner than that from grain-fed animals. More animals could be raised on less grain, allowing them to perform their traditional agricultural role of converting material humans can’t eat – grass, crop residues, food waste and surpluses – into human food and fertiliser.
But the world’s grazing land, the chief source of otherwise unusable fodder, is already at or near capacity, and 20 per cent is overgrazed. One hope is for more widespread use of improved fodder plants, especially legumes such as vetch that fix nitrogen. Another is closer management of rangeland to prevent overgrazing and erosion. On some fragile soils in arid areas, native wildlife may cause less damage than the usual cattle and sheep (see “Roast roo anyone?”).
Still, as long as farmers can sell a kilo of grain-fed meat for more than the cost of the grain, they will feed grain to livestock. But there are ways to mitigate the environmental cost. Once again, rigid organic doctrines may stand in the way of environmental progress. Genetically modified maize that produces protein more suited to livestock requirements not only increases feed efficiency, but generates manure that contains less nutrients, especially nitrogen, resulting in less pollution of waterways and even less stench (91av, 18 March 2000, p 32).
Roast roo anyone?
“The Skippy syndrome is dead in Australia,” says John Kelly. As development manager for the Kangaroo Industry Association, Kelly has a vested interest in persuading Australians to eat their national emblem, but his claim is supported by the statistics. In the past 10 years, the domestic market for kangaroo meat has shot up fiftyfold.
And it’s not only Australia that tucks into its local fauna. Across the New World and Africa, there’s increasing interest in “indigenising” livestock. Rather than continuing to change the environment to suit European sheep and cows, say proponents, why not harvest animals like crocodiles, caribou and impala that belong there in the first place? Some conservationists fear that turning wildlife into a commodity will lead to over-harvesting, especially if wildlife meat becomes so popular it exposes the industry to the full clout of market forces. But it could also help protect the environment from some of the worst ravages of intensive farming.
Take Skippy. Today, wild kangaroos merely add to the burden on land overgrazed by sheep and cows. Turn kangaroos into a cash crop and you won’t need as much domestic stock. Plus, the big-footed roos do less damage to fragile land than cloven-hoofed sheep and cows. “Within 20 years, we hope to see that some properties have cut their sheep altogether – some by a third,” Kelly says.
Farming goes to town
Much of the world’s food doesn’t come from conventional farms. Around 15 per cent is grown in urban areas, according to the UN Development Programme’s urban agriculture network-and the figure is rising all the time. Hong Kong, the densest large city in the world, produces two-thirds of its own poultry, a sixth of its pigs and half its vegetables. So too could less densely settled cities, say experts. Even London could grow a fifth of its fruit and vegetable requirements using the city’s composted waste, according to Sustain, a London-based green research organisation.
“Urban farming goes far beyond gardening,” says Jac Smit, president of the UNDP network. “It creates green spaces, recycles waste, cuts down on traffic, provides employment, substitutes for imported high-value goods, prevents erosion, and is good for the microclimate.” Urban vegetable production also uses less than a fifth as much irrigation water as mechanised rural cultivation. Recent studies in the Philippines and elsewhere have linked better child nutrition to the local production of food in urban areas, he says.
Because they tend to be small and carefully tended, urban farms also tend to be far more productive than their larger rural counterparts. A study in Nairobi, Kenya, by a development project in the city called the Mazingira Institute, found output averaged 9 tonnes per hectare, more than twice rural yields. The highest productivity was on the smallest plots, even though most farmers didn’t use yield-boosting chemicals.
Farming in the heart of cities has its risks, of course. It can bring people into close contact with pesticides, and with livestock, which can carry human diseases. The practice of fertilising crops with human sewage also brings considerable hazards. In Peru in 1992, for example, sewage water used to irrigate urban crops helped spread cholera. Leafy vegetables also soak up air pollution, especially lead from exhausts, which then ends up on dinner plates.
Still, for a world in need of abundant, reliable food sources, urban farming plays a vital role. But for now, says Smit, “urban agriculture remains the Cinderella of food production, ignored by city authorities and agricultural researchers alike”.
