Professor Jon Oatley was beside himself with excitement. He was announcing to the world a breakthrough that could transform animal breeding. Gene editingChanging or removing the DNA coding in embryos. Critics argue that it can harm animals, and that the latest technique - developed with mice - may not actually work on cattle. now makes it possible to produce animals that are born sterile but can then be injected with sperm-producing cells from the best of their breed. An ordinary bull will be able to father offspring with the characteristics of a champion.

For some experts, though, this is one more example of scientists tampering dangerously with nature. In his new book English Pastoral, James Rebanks argues that abandoning traditional farming practices in favour of advanced ones has been disastrous. The pursuit of high profits from cheap food has put small farmers out of business and done huge damage to the environment.

The key to farming, he says, lies in the fertility of the soil. If a field is used over and over again for the same thing, every crop will use up more of the soil's nutrients until it ceases to be healthy and pests and diseases proliferateIncrease in number. In botany it refers to developing buds or shoots, and in biology to cellular division..

The solution embraced by medieval farmers was rotation. A field might be used for growing first oats and then wheat, then given over to grazing for sheep or cows. At each stage, it would receive new nutrients - from the crops' rotting leftovers or from the animals' manure. Finally, it would be left fallow to recover.

In England, the peasants' land was divided into strips, and one family might have several of these in different places. If disease or pests affected one plot, the family would still have enough food from the others.

Cattle, meanwhile, were kept increasingly in sheds instead of grazing the fields. Farming changed dramatically with the introduction of modern machinery. And to cut costs everything was done on a much larger scale, with ancient hedgerowsBarriers made from trees and shrubs, they mark the limits of fields and protect them from the wind. They are also home to many birds and small animals. torn out to create bigger fields. All these changes required investment that farmers often could not afford. Many went out of business, and giant corporations took over their land. In the USA today, prairie farms may be so large that it can take several hours to drive across one of them.

The greatest revolution came with the spread of artificial fertilisersThe most important of these is ammonium nitrate, first used to make explosives. in the second half of the 20th century, first in the US and then elsewhere. By adding these to the soil, farmers could grow a single crop repeatedly.

But the fertilisers have proved to be a quick-fix solution. Rebanks compares them to the drugs taken by addicts: stronger and stronger doses are needed to achieve the same effect. Meanwhile, the ecosystems that rotation farming maintained are being destroyed.

Rebanks tells of an elderly farmer, Henry, who was mocked for sticking to old-fashioned ways and refusing to modernise. When he died, another farmer bought some of his land and sent the soil for analysis, wanting to know what fertiliser he should add.

The answer came back: this was some of the healthiest soil the laboratory had ever tested. There was no need to add fertiliser at all.

Some say, no. The world's population in the 13th century was vastly smaller: around 400 million as opposed to 7.8 billion today. Only intensive farming methods enable so many people to be fed. Common diseases that destroy crops can now be combated with pesticidesPoisons used for destroying insects and plants. and genetic engineering. Scientific breeding produces cattle providing far more meat and milk than they did in the past.

Others argue that there is a delicate balance in the natural world that modern farming disrupts. It ruins not only the soil but the habitats of many wild creatures, threatening the biodiversity on which our survival depends. The quality of food produced in countries like Romania, where traditional methods are still widely used, is much higher than elsewhere, and much better for people's health.