The world’s population will grow from almost 7 billion now to over 9 billion in 2050. John Parker asks if there will be enough food to go round
THE 1.6-hectare (4-acre) Broadbalk field lies in the centre of Rothamsted farm, about 40km (25 miles) north of London. In 1847 the farm’s founder, Sir John Lawes, described its soil as a heavy loam resting on chalk and capable of producing good wheat when well manured. The 2010 harvest did not seem to vindicate his judgment. In the centre of the field the wheat is abundant, yielding 10 tonnes a hectare, one of the highest rates in the world for a commercial crop. But at the western end, near the manor house, it produces only 4 or 5 tonnes a hectare; other, spindlier, plants yield just 1 or 2 tonnes.
Broadbalk is no ordinary field. The first experimental crop of winter wheat was sown there in the autumn of 1843, and for the past 166 years the field, part of the Rothamsted Research station, has been the site of the longest-running continuous agricultural experiment in the world. Now different parts of the field are sown using different practices, making Broadbalk a microcosm of the state of world farming.
The wheat yielding a tonne a hectare is like an African field, and for the same reason: this crop has had no fertiliser, pesticide or anything else applied to it. African farmers are sometimes thought to be somehow responsible for their low yields, but the blame lies with the technology at their disposal. Given the same technology, European and American farmers get the same results.
The wheat bearing 4 or 5 tonnes a hectare is, roughly, like that of the Green Revolution, the transformation of agriculture that swept the world in the 1970s. It has been treated with herbicides and some fertilisers, but not up to the standard of the most recent agronomic practices, nor is it the highest-yielding semi-dwarf wheat variety. This is the crop of the Indian subcontinent and of Argentina.
The extraordinary results in the centre of the field are achieved by using the best plants, fertilisers, fungicides and husbandry. The yield is higher than the national average in Britain, and is as good as it gets.
But the Broadbalk field shows something else. Chart 1 tracks its yields from the start, showing how the three different kinds of wheat farming—African, Green Revolution and modern—have diverged, sometimes quite suddenly: in the 1960s with the introduction of new herbicides for Green Revolution wheat, and in the 1980s with new fungicides and semi-dwarf varieties. Worryingly, though, in the past 15 years the yields of the most productive varieties of wheat in Broadbalk have begun to level out or even fall. The fear is that Broadbalk may prove a microcosm in this respect, too.
At the start of 2011 the food industry is in crisis. World food prices have risen above the peak they reached in early 2008 (see chart 2). That was a time when hundreds of millions of people fell into poverty, food riots were shaking governments in dozens of developing countries, exporters were banning grain sales abroad and “land grabs” carried out by rich grain-importing nations in poor agricultural ones were raising awkward questions about how best to help the poor.