Arable News

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Making sense of soil

Last autumn’s difficulties in establishing winter crops have highlighted the fact that nothing is more important than the soil in determining the success, or otherwise, of planted crops

If nothing else, last autumn’s difficulties in establishing winter crops have highlighted the fact that nothing is more important than the soil in determining the success, or otherwise, of planted crops. Dominic Kilburn talks to an adviser who reckons a shift in emphasis in the overall understanding of soil in the UK is needed if future demands on crop production are to be realised.

Andrew“It’s no good having great crop varieties and fungicides if the soil cannot sustain what’s growing in it,” stresses agronomist and business development manager for Agrii, Andrew Richards (left). “Soil is an area that needs to be managed better,” he points out. “It’s an art form – it’s not just about managing clay or a sandy soil. Continuous variations in moisture content, on any given day, mean a soil can behave in a completely different way and needs to be managed accordingly.”Andrew is based near Banbury, in Oxfordshire, and advises growers in the north of the county as well as in Buckinghamshire. He has recently taken up the role of chair of the Soil & Water Management Centre – a national initiative based at Harper Adams University intent on improving the productivity and resilience of UK farming through more careful management of its two most important resources.”There’s a lack of credible, independent advice on soil and  a strong recognition in the industry that we must transfer more applied research into practical action – and that’s why we started the initiative,” he claims.”We wanted to get people to start thinking about soils again as most issues about soil management in recent years have been about pollution, and there has been very little spoken about soils in relation to the challenge of increasing food production.”Agriculture must get its approach to soil right if it is to stand a chance of getting the rest of the production and agronomy right,” he adds.With most areas of the country receiving an average of 150 per cent above their normal rainfall levels last autumn, and in some cases as much as 180 per cent above, 2012 has officially been recognised as the UK’s second wettest recorded year. Andrew suggests that many soils in the UK are currently in a very fragile state and, in some cases, still far too wet to travel on. “Last year we saw a lot of compaction damage created at harvest and during crop establishment.
“In addition, there will be some growers whose land has just come out of potatoes, for example, who have harvested a very poor quality crop and will now be considering if damaged land will be suitable for a crop within the next 12 months.” While light, free-draining soil has fared somewhat better in the conditions, over cultivated light land has been at risk from erosion, he adds.
Andrew stresses that if growers want to focus more on their soil management, then they need to go back to the basics and put right the primary problems affecting soil structure. “Drainage is key,” he states. “It isn’t cheap, and it’s an area that has seen under investment for many years following the withdrawal of grants coupled with poorer returns. But growing crops is also expensive and growers should prioritise areas of the farm that suffer from poor infiltration, as improved drainage  will result in higher yielding crops which also compete better with black-grass. “Soils must be allowed to dry by improving drainage systems and cleaning ditches out before getting on to the land again with heavy machinery.”
According to Andrew, the process of damaging soils seems to be accelerating with the combination of weather extremes and the tendency to use larger kit on farm. “We’ve pretty much reached a maximum size of machine which is used on farm and the benefit of some heavy kit is that it consolidates so much better and, in turn, produces better seedbeds with reduced slug problems. But if these weather extremes are to become the norm, we need to do something about soil structure to support the machinery and we need good science behind our approach.”He says that the increased adoption of minimum tillage has exacerbated the problem of compacted soils with problem pans at depths of three to four inches. “People want to save money by using min-till. But with bigger and heavier kit, wet soils, more winter cropping and tighter working windows; soil structure is struggling to cope.With bigger and heavier kit, wet soils, more winter cropping and tighter working windows; soil structure is struggling to cope.“More organic matter is vital and I don’t think the straw being put back in via min-till is enough to make a significant difference,” continues Andrew. “However, there is an increasing amount of green waste compost now available and the use of materials such as bio-solids and cover crops should be considered to boost organic matter levels.”I have growers regularly applying compost to lighter land and achieving respectable winter wheat yields of 9t/ha. Increased levels of organic matter have improved soil structure to the extent that, last autumn, composted land was all drilled up well ahead of non-composted neighbouring land.”Growers have to question whether their soils have enough organic matter to sustain a proper structure,” he stresses.
Andrew points out that a limited chemical arsenal, weed resistance and climatic variability mean it is also becoming increasingly important to manage soils and tillage effectively to control the burgeoning problem of black-grass – the spread of which is directly related to soil condition and drainage issues.He says that in an Agrii survey of growers carried out last autumn, it was recognised that black-grass had become a serious problem extending well out of its traditional geography of the Midlands and southern England. “It’s a big issue across a wide area and while the survey showed that 50 per cent of growers are now looking to ploughing as a means of reducing the impact of black-grass, and the same percentage again looking to change their rotations accordingly, no one system is delivering the answer. Farmers really have to look at what they are doing about controlling it,” he comments.”Delayed drilling helps enormously with black-grass control, but how many growers will delay their drilling in autumn 2013 after last autumn’s experience?” he adds.
Andrew says that patience has a big part to play in growers’ strategy for planting this spring, reminding them that spring barley can be drilled safely up until mid-April. “The key thing with spring crops is that they like to get away quickly, so allow the weather to do what it can to get the water away before drilling.”Get out there with the glyphosate and hit the black-grass where possible, and use a tined cultivator rather than discs to get air into the soil. More than anything wait for conditions to be right.”
He adds: “Nutrition will be vital this spring too – do everything you can to get the crop away with fertiliser in the seedbed and early-applied foliar nutrition to encourage rooting and tillering.”


Taking the lead in soil improvement
The Soil & Water Management Centre is a national initiative by Harper Adams University and leading businesses and organisations to improve the productivity and resilience of UK farming through more careful management of its two most important resources.With Agrii, Vaderstad, GrowHow, The Co-operative Farms, Agco Challenger, Michelin, Interagro, BASIS, NRM Laboratories and the Rothschilds Education Trust as founder partners, the initiative is widely supported by leading specialists and organisations throughout the farming community.It has secured three-year funding to establish a permanent centre at Harper Adams with a director and new chair of Soil and Water Management at the University.
“Modern food production systems – not to mention climate change – are putting our most vital agricultural assets under more pressure than ever before,” stresses Agrii agronomist, Andrew Richards who chairs the initiative.
“Across the country we’re seeing the direct result of this pressure in soils with increased compaction, reduced biological activity and an impaired capacity to buffer both drought and flood.”We’re putting soil and water management firmly where it needs to be – at the centre of UK agricultural improvement efforts,” Andrew insists. “Most encouragingly, we’re getting all sides of the industry working together to a common goal; a goal which appreciates that all our farming futures depend, more than anything else, on the healthiest, most productive, most weather-tolerant soils.”


Drains are a priority
It is vital that land is managed well between now and the end of the spring to avoid further damage to soils, says Miles Drainage contracts manager, Andrew Wright.
With the Suffolk-based company celebrating 25 years of business this month, he points out that growers must ensure they keep off saturated land and wait for it to dry out properly. He also suggests that use of power harrows should be limited as, although a fine tilth may suit an establishing crop, it often prohibits water flow down through the soil profile. “The trouble is that field drains are ‘out of site and out of mind’ and with farms set up now with approximately one man per 1,000 acres, the maintenance and repair of drains is often overlooked.”Farmers can help themselves though by simply checking drain flows, clearing blockages and ensuring ditches are clear,” he claims.According to Andrew, prices for drainage typically range from 600-1,000 per acre and are not prohibitive. “Our advice would be to select parts of the farm that need attention most. Many of our customers don’t do it all at once, but do smaller areas regularly.”

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