Stopping erosion in its tracks
The plea to take our soil health seriously is a strong one - our food, our safety and our climate depend on it - but how do we go about taking better care of our soils? Is it possible to rejuvenate our soils and if so how? Soil ecologist Richard Bardgett from Manchester University took Kat Arney through the options...
Richard - It certainly is possible to rejuvenate soils and it’s quite remarkable, when you look around the world at soils that have been affected in the past, how resilient the really are. I mean, you can find soils that were completely obliterated during the First World War that are now showing signs of soil health and restoration; so it really depends on the extent to which they’ve been degraded. But I think one key thing about restoration of soils is that the rate of soil formation is extremely slow. I mean, where I live around here, most of our soils are around 10,000 years old and they will have formed about 1 metre of soil. So it takes, on average - I mean it varies, obviously, from place to place - but about 1.1mm of soil is formed per year on average; so it’s a very slow process. But, having said that, there are things you can do and John’s mentioned a few. I mean the first is stopping the forces that cause soil degradation like continuous cultivation, etc., and really key to it is restoring the organic matter and recycling of nutrients within the soil system.
Kat - So my mum is a keen gardener and, you know, I always think if you want to improve your soil you just chuck a bag of manure on it. Is that the main solution or are there other ways of preserving soil and making it better?
Richard - Well that might be a good solution in a garden but I don’t thinks it’s going to be a solution to restoring soils around the world. I think key to restoring them is getting organic matter back in them and restoring the soil community – the food web or the living soil – all the different types of organisms within there and that, to me, is really crucial to restoring soil functions within degraded landscapes.
Kat - So does this mean changing the way we use soil? Changing the way that we farm basically?
Richard - Absolutely, and there are certain things that you can do relatively easy in some parts of the world. I mean there’s different cropping practice like crop rotations, no till agriculture which is a form of agriculture where the ground isn’t ploughed, but the other thing you can do is by selecting different types of crops that can actually promote beneficial organism in the soil.
Kat - Given that it does seem to be the way that we’re farming that’s leading to quite a lot of the degradation in our soils, the loss of our soils, and changing to more sustainable farming methods that are kinder to our soils. Are we still going to be able to feed a growing population?
Richard - I think a lot of the management options potentially have a trade off in terms of short term yield reductions but I think there is a possibility, through things like crop breeding and engineering of the (03.03), for example. We are beginning to learn that roots exude different kinds of chemicals through them which act as signals to warn crops of oncoming pests, for example and, also, we’re beginning to learn that different root characteristics, or combinations of root characteristics, can promote the growth of certain bugs in the soil which improve nutrient acquisition, etc. So I think it’s certainly something we can’t ignore for the reasons that we’ve talked about.