Arable News

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Soil management myth-busting September 2018

Steve Townsend winds up his special Myth-busting series which has featured in Farmers Guide over the past few months by addressing perhaps the most crucial soil management myth of all.

“Healthy soils will make your life easier”

Healthy soils do a lot for us. They reduce our need for fertiliser. They make our crops much better at dealing with drought and flood. They help us manage black-grass and other problem weeds. And they give us healthier crops, less prone to disease.

Our cropping life is much less risky and far more sustainable with healthy soils. But one thing it isn’t, is easier. If anything, in fact, it’s more complicated and demanding.

How so, I hear you ask. Surely, leaving crop residues on the surface and cutting down on tillage means more time. Just as improving soils with organic manures and cover crops means less ‘climate anxiety’. And getting soil calcium levels as well as pH right works wonders for soil structure as well as fertiliser responses.

Of course they do. However, the key thing we have to appreciate about improving soil health is that it’s not one of the easy ‘out-of-the-can’ agronomic fixes we’ve become so used to over the years. Ask any organic grower. Healthy soils take real effort and not a small amount of time to achieve. And maintaining them is altogether more difficult than the ‘more-metal-through-the-ground’ approach that has become the soil management solution of choice in far too many cases.

Think about it. We’re managing around a cow’s weight of biology per acre at the moment and we’re increasing our ‘stocking rate’ to the equivalent of five cows. More productive? Yes. More economic? Almost certainly. But easier? Hardly.

Healthy soils require considerable thought and planning to achieve in the first place. We can’t just ladle on lashings of whatever organic manure is easiest to get hold-off, for instance. Instead, we have to apply manures that provide the best support to soil biology as well as extra carbon; apply them in the right amount; and apply them in ways which don’t damage the very soils we’re trying to improve. Or perhaps, as I prefer, we can rely on cover cropping, crop residues and the least possible tillage to do the same job with far less risk.

But this isn’t easy either. If winter cover crops are to really support the biology and structure of our soils we have to manage them right. We have to select the right mixtures of species, establish them well enough, and destroy them effectively far enough ahead of spring drilling to give us the best conditions for the following crop. Otherwise we’re likely to find them little more than a costly waste.

Crop residues

Equally, if we want to make the most of our crop residues we should leave them on the surface rather than incorporating them. Again, though, this is easier said than done. It demands the most effective straw chopping and spreading, together with the right approach to dealing with slugs and autumn wetness – both of which can cause difficulties.

Which brings us to direct drilling. I have absolutely no doubt that the no-till approach is the most sustainable way of improving soils. However, we can’t just move into it overnight and expect everything to get better. We need to steadily reduce our tillage over several years to allow the soil structure to build from depth. We have to use heavier cultivator drills with particular care in the early years. Initially too, we have to be prepared to provide some extra nitrogen, phosphate and sulphur to support our developing soil biology so it doesn’t consume these key nutrients at the expense of our crops.

At the same time, of course, in securing the most resilient soils we also have to think calcium as much as pH with our liming. That way we make sure we get the best nutrient balance for soil structure and functioning as well as crop nutrition.

I’d like to be able to tell you that life gets easier as soil health improves. Unfortunately, it doesn’t. Mainly because the high performance biological engines our soils now have need to be continually maintained and tuned to keep them running sweetly.

After all, five cows to the acre take far more feeding and husbandry than one. And the consequences of getting things wrong are far greater if either is lacking. If it can’t get enough winter nutrition from cover crop roots, for instance, the soil biology can rapidly consume our carefully built-up carbon store. Or we can hit it, and our natural soil structure, hard with a single ‘killer’ cultivation at depth.

No, healthy soils will not make our lives easier. But I know improving soil health will make our cropping so much better in all the ways I’ve touched upon in this series. And, in my experience, at least, few of things that are most worth doing in life are easy.

Myth-buster, Steve Townsend is more than happy to discuss any tillage or soil management issues, interests or concerns with Farmers Guide readers by email on [email protected] or by phone on 01452 862696.

  • Written by: Farmers Guide
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