WITH one-third of arable land lost in the past 40 years, no-till agriculture is key to a farming future according to UK researchers speaking at the Paris climate conference.
The experts warned that soil loss is an unfolding global disaster and will have a major impact on meeting world food production needs.
University of Sheffield Professor of Plant and Soil Biology, Duncan Cameron, said soil loss occurs rapidly but takes hundreds of years to be replaced.
“This represents one of the greatest global threats for agriculture,” he told the conference.
“Erosion rates from ploughed fields are on average 10 to 100 times greater than rates of soil formation.
"This is catastrophic when you think that it takes about 500 years to form 2.5cm of topsoil under normal agricultural conditions.”
The University’s Grantham Centre for Sustainable Futures report said the current intensive agriculture model is unsustainable as intensive farming sees crop yields maintained through heavy fertiliser applications.
This means high energy inputs are needed to supply inorganic nitrogen via industrial processes that consume five per cent of the world’s natural gas production and two per cent of the world’s annual energy supply.
It also depends on the mining of non-renewable and increasingly diminishing stocks of rock phosphorus, and sees nutrients wash-out of soils polluting fresh and coastal waters.
The team said “elite modern crops are optimised for a system of high nutrient artificial inputs and chemical control of pests and diseases; they have consequently lost their natural reliance on microbes to extract complex nutrients from the soil and for defence against natural enemies.
“Soil is becoming a hydroponic system: a physical substrate to support plants, but providing little else.”
The report outlined three key principles to drive a sustainable agriculture model including managing soil by direct manure application, rotating annual and cover crops, and practicing no-till agriculture.
These “conservation agriculture” practices restore soil organic matter, structure, water-holding capacity and nutrients, averting soil loss and benefiting crops.
Secondly, it is recommended biotechnology is used to “wean crops off the artificial world we have created for them, enabling plants to initiate and sustain symbioses with soil microbes”.
This would allow crops to exploit microbial biology to tap into soil organic nutrient reserves, and prime plants to better defend themselves against pests and diseases.
Finally, the Sheffield team said recycling nutrients from human sewage in “a circular economy” could see inorganic fertiliser manufactured in biorefineries operating at either an industrial or local scale.
While technical challenges currently restrict this idea, research would be key to furthering this opportunity.
The report said a soil focussed reengineering of agricultural system would reduce the need for fertiliser inputs and pesticide application, require less irrigation, and contribute to safeguarding the finite natural resource.
For further information see grantham.sheffield.ac.uk