Arable farmers looking forward to Cereals on 11-12 June (arguably the most comprehensive exhibition left in this country for our sector) might pause a moment and cast their minds back three or four decades.

Mature readers will recall those days with ease. For those still in short pants then I will explain. I will then suggest some implications for today.

In Belgium a university professor named Laloux was developing new methods of growing wheat to maximise yields. Counterintuitively, he cut seed rates. He increased nitrogen applications and sprayed with sulphur-based chemicals. During the 1970s he achieved notable success and farmers from all over Europe beat a path to his door.

Concurrently, in Schleswig-Holstein in Germany, scientists and agronomists were working on a similar project. They split nitrogen top dressings into three applications and used the more refined fungicides being developed by German ag chem manufacturers.

Multiple applications of these products meant running through crops several times a season so they devised integrated systems of drilling, fertilising and spraying along the same wheelways – or what we in Britain soon began calling tramlines.

It’s all commonplace now, of course, but at the time it was revolutionary. Previously we had drilled the crop, applied a bit of nitrogen and herbicide, then shut the gate until harvest time. Yields of 5t/ha (2t/acre) were considered excellent.

But suddenly, during just one decade from 1973 to 1983, with the help, it’s true, of better varieties of wheat, many from the long-lamented Plant Breeding Institute at Cambridge, yields doubled. I well remember in 1983 on our farm we averaged 10t/ha (4t/acre) of wheat across the whole farm.

Sadly, 30 years later, that is still a target we aim for and don’t always achieve. As on most farms, our yields have not consistently increased since then. And average national yields are not much more than 8t/ha. Surpluses were an embarrassment 30 years ago. In the near future it seems likely the world will need every grain we can grow.

So, why did we enjoy such success during the 1970s and why did yield increases grind to a halt in the 1980s? I believe there were two main reasons. The first was political. Intervention stores were full and support to produce farm commodities was seen as an unnecessary drain on EU resources.

We saw the beginnings of disincentives to grow big crops and the rise of environmentalism. The balance between the two has still not been rationalised to match different conditions today.

The second reason was that during those first 10 years of our EU membership we had guaranteed prices via the intervention system and were able to make good margins.

Farmers had money to invest in new tackle and scientists were motivated by farmers wanting to know more and grow more. Perhaps we overdid production because of our enthusiasm. We were certainly producing ahead of demand.

These days, the theme is sustainable intensification. In other words, we must protect the environment but at the same time respond to growing demand. But financial motivation is vital. Decent margins were what generated success in the 1970s and that is what it will take to exponentially raise production again.

Volatility and mediocre returns won’t do it. We need good profits and stability to produce the goods to feed all the extra mouths in the world. Politicians of the world, please note.

David Richardson farms about 400ha (1000 acres) of arable land near Norwich in Norfolk in partnership with his wife Lorna and his son Rob

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