Using far less chemical fertiliser still produces high crop yields, study finds

theguardian.com:

Farmers could continue to produce high crop yields with far less use of artificial fertilisers if they adopted environmentally sustainable practices, an academic study has shown for the first time.

Techniques such as adding manure and compost to soils, growing nitrogen-fixing plants between crops, and cultivating a wide range of produce instead of sticking to the same crops, can all increase yields while protecting and improving the natural ecosystems of farms.

Adopting these practices would be enough to replace a substantial proportion of chemical fertiliser, the price of which has soared owing to high fuel prices and the war in Ukraine, the study found.

Chloe MacLaren, a plant ecologist at Rothamsted Research in the UK who is the lead author of the paper published on Monday in the peer review journal Nature Sustainability, said: “Reducing reliance on chemical fertilisers would help to buffer farmers and consumers against economic shocks, such as the current spike in fertiliser costs and consequent increase in food prices. Widespread uptake of these practices could also contribute to a more equitable global distribution of fertiliser.”

In the study, scientists analysed 30 long-running experiments on farms in Europe and Africa to assess how natural farming methods could improve yields.

They found that using sustainable farming techniques did not increase yields when used on top of high applications of fertiliser, on the scale normally used in farming, but produced the greatest yields when practised with the addition of some nitrogen to soils.

Each of the experiments analysed was running for more than nine yearsand all together the study covered data from more than 25,000 harvests of six crops: wheat, maize, oat, barley, sugar