Water management is the topical focus of the second of our monthly articles exploring the benefits and practicalities of a modern no-till approach
Article by Steve Townsend Water management is the topical focus of the second of our monthly articles exploring the benefits and practicalities of a modern no-till approach to arable improvement by leading soil husbandry specialist, Steve Townsend of Soil First Farming.Too much of a good thing
This time last year we were crying out for it. But since then our desires have been tempered by a good 10 months of continuous rain. This has certainly made us appreciate just how vulnerable our cropping systems – or more accurately our soils – have become.
The wettest year in England and Wales since 1872 has left us with a legacy of slumped, compacted, capped, rutted and otherwise damaged soils. And with it pools and ponds where we have never seen them before; seriously silted drains and ditches everywhere we look; and, huge concerns over our future as well as current cropping.
Yes, it’s been unbelievably wet in most parts of the country, badly delaying winter plantings on all but the lightest of soils. But the plain fact is the vast majority of our more productive, heavier ground could have coped far better were it not for the fact that too many of us have over-borrowed so badly from the ‘Bank of Soil Organic Matter’.
This has been clear wherever I’ve been working with growers to improve soil structures by naturally re-building organic matter with a no-till approach. Despite being drilled every bit as late as most, we’ve seen crops under this system picking-up earlier and growing away far faster than those under conventional tillage this spring. It all comes down to healthier soils, better able to resist structural damage and allowing the best possible water infiltration.
Tillage has a value in loosening and aeration. But unfortunately this is all too temporary. Mainly because introducing air into soil burns up organic matter through oxidation – destroying the micro-flora and fauna that, with decaying vegetation, form the ‘soil glue’ binding individual particles into aggregates which hold together robustly through repeated cycles of wetting and drying.
Resilient aggregates means a soil structure with abundant inter-connecting micro-pores, retaining far more moisture and nutrients through capillary action; each ounce of soil organic matter holding many times its own weight in water.
They also mean more stable macro-pores for the most rapid and complete infiltration of surface water. They actively resist compaction. And they allow the soil to breathe, creating the most efficient and productive aerobic conditions for a thriving living system.
Tillage interrupts all this. It wipes out massive numbers of soil micro-organisms and the living plant cover and roots that are their natural habitat. Declining levels of organic matter result in a progressive loss of soil structure, water-holding ability and infiltration capacity. Conditions turn increasingly anaerobic and lifeless. And the ground becomes more and more vulnerable to both deluge and drought, not to mention traffic.
In my experience this vicious downward spiral can only be addressed by reducing, if not completely eliminating, field-scale tillage; confining seedbed preparation only to the immediate area of soil into which the seed is actually drilled.
This sort of informed no-till approach leaves the remainder of the ground untouched to build up the healthiest possible structure, making increasing deposits to, rather than withdrawals from, our most important ‘Bank’. It also employs crop residues and cover crops to add organic matter and improve soil vitality.
It will take time to fully turn around years of soil abuse. But after just three seasons we’ve seen a really positive impact on soil conditions under the excessive rainfall of the past 12 months. And we’re finding equally valuable improvements in our soil’s ability to store moisture for grain fill – highlighted by HGCA as a key reason for the yield plateau experienced across much of south and east England.Next month Steve Townsend will be turning his attention to cover cropping. He is more than happy to discuss any tillage or soil management issues, interests or concerns with Farmers Guide readers by e-mail on [email protected] or by phone on 01452 862696.