On Easter Sunday we sang the hymn ‘Now the green blade riseth from the buried grain’. My mind wandered away from the service and to how fortunate we are in the UK to have both the weather and the soils that can sustain good crops of grain. Of course the hymn book, from an agricultural point of view, gets really revved up for harvest festival. There are hymns that convey the labour and planning that lie behind producing a crop and the age-old worry about the weather. ‘Hopes of sun and rain’ is from a hymn written by John Arlott, who is more remembered for Test Match Special (if you are old enough) than for anything else.
When you look at an atlas (or on Google Earth!) it is surprising to see that we farm at a more northern latitude than the Canadian prairies - noted for vicious winters and hot summers. Yet we have relatively mild winters and summers. So why are we so successful at growing wheat?
The explanation is clear; we have a maritime climate warmed by the Gulf Stream. In fact, look at the countries with the highest wheat yields - they are all islands that benefit from the moderating effects of the surrounding seas.
The Republic of Ireland has the highest average wheat yields in the world, followed by New Zealand; I believe the UK is in third place. New Zealand is capable of extraordinarily high yields, but these can often be achieved only with irrigation at the end of the season.
The reason for this very high yield potential is that, despite having the same number of days during grain fill (flowering to maximum yield at around 35% moisture content) as the UK, NZ accumulates yield at a rate about a third higher than ours.
My calculations suggest that, on average, the UK accumulates wheat yields at a rate of 0.23 t/ha a day during grain fill whilst in New Zealand the rate is 0.30 t/ha. This is because the Canterbury Plain is on the same latitude south as the very south of France is north. So, despite having the same temperatures as East Anglia during grain fill, their solar radiation is much higher.
It’s not only the weather but our soils that have in the past provided us with such a great advantage. They are relatively young and have not been leached of nutrients as have the very old soils in some other parts of the world. This meant that during the development of agriculture, when there was little or no knowledge of plant nutrition, we had a natural advantage.
Of course it is important that we exploit our natural advantages. Pesticides and plant nutrients have enabled us to tap much of that potential. But, we now seem to have reached the point where any further yield increases are incredibly hard to achieve. Not only that but some of the technologies that enabled us to exploit these natural advantages are under pressure because of pesticide resistance and/or from regulation.
What we need is more technology, and not less, if we are to play the role in food production that society now increasingly recognises as essential.
There are still those who argue that we should have less technology and we should return to more ‘natural’ methods. I cannot agree with this and that's why I was a bit upset by a recent letter to Farmer’s Weekly regarding the GM wheat trial at Rothamsted Research. The letter questioned why a milling spring wheat, a relatively minor crop in the UK, was being used, and that no-one would use the flour produced.
The letter is missing the point. Rothamsted Research is a scientific institution and this is an experiment into what may, or may not, be possible. To stop science’s quest for knowledge on such arguments is an attempt to stop the clock. It goes to show the lack of coherence in the objections to GM. Surely, even if you are against multinationals allegedly taking the easy options, such as herbicide tolerance, to make profits from GM, why object to a scientific study of the possibilities it may offer?
It is widely acknowledged that we are still in the early stages of using biotech to improve crops and so today’s commercial products should not be used to damn the technology. I live in Cambridge, the birthplace of internet usage. It was in the University’s computer lab where a picture of a coffee pot, the Trojan Room Coffee Pot, could be accessed on all the VDUs to see if it was sufficiently full to make the foot journey to replenish cups/mugs worthwhile. That surely is a technology without a future.