IT is 400 years since a man nicknamed “Turnip” Townshend revolutionised British farming by introducing what became known as the Norfolk four-course rotation.

He recognised that continuously growing the same crop on the same land year after year reduced yields due to lower fertility and increased plant diseases.

The inclusion of leguminous clover increased the natural nitrogen available for following crops and the introduction of turnips once every four years broke the cereal disease cycle as well as providing an excellent livestock feed for the mixed farms of the day.

With only about 3 per cent of today’s food being produced by truly organic methods, most farmers rely on scientifically developed pesticides and artificial nitrogen to boost crop yields, but almost every grower still uses a crop rotation.

Some pests and diseases cannot be totally controlled by pesticides.

Weed control is improved without a reliance on the herbicide available for one crop type and soil health is maintained by growing some deep rooted crops and others such as peas or beans which “fix” nitrogen from the air. Every year arable farmers spend some time considering their cropping plan.

The most profitable of local crops which can be combine harvested is usually wheat but it is also the crop which suffers most from continuous cropping. Fungal disease in second and third year wheats devastate yields.

Wheat is sown in September and harvested in August or September which means a very short period between harvest and re-sowing. Competitive weeds such as
blackgrass take advantage of the situation by germinating in September.

Farmers can counteract this by waiting until spring and sowing a different crop.

Over the last 40 years or so the most popular, and profitable, break from cereals has been oilseed rape.

For reasons stated in previous articles there has been a dramatic drop in the area sown locally and it is sad for the farmers, and the bees, that there will be less yellow fields in evidence this spring.

About 1 million tonnes less will be produced here in 2017 with production being taken up in the Americas, Ukraine and Australia where neonicotinoid sprays remain widely used.

What are farmers growing instead? Spring sown barley has certainly made a comeback - a relatively easy crop to grow but not a “break” from cereal diseases.

There is great encouragement in EU rules to grow more peas and beans - these provide a good break and add natural fertility to soil but over production and lower prices make these less attractive. Linseed has also made a bit of a comeback but its late, and sometimes difficult, harvest can be an issue.

On our own farm we concentrate on a selection of niche crops such as borage, echium and our own variety of quinoa. Some of these are particularly good for bees and the environment but because demand is limited they will never become mainstream farm crops.

Maize is being grown for cattle feed and green energy production.

On lighter land, particularly with irrigation, potatoes, onions and other vegetables remain options and with new uses now being found for sugar beet we could even see a revival in that crop.

So, it seems, no rotation is perfect but “Turnip” Townshend would be happy to note the principles he expressed are still just as relevant today.