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I’ve a good friend –– we’ll call him John.He’s dependable and supportive, the sortof friend you can rely on. But he’s alsounpredictable –– you’re never quite surehow John’ll react at a particular occasionor situation.

As the years have gone by, and both our lives havechanged, John has become no less unpredictable, butI’ve got to know the sort of situations in which he reallythrives and the occasions at which I need to apply a little more caution –– I guess that’s what turns a relationship into a lasting friendship.

I’d say most growers have a similar relationshipwith their soil. You can never predict exactly whatthey’ll do –– how they’ll react to a piece of cultivationkit or to a new tractor, for example. But you get aninkling of the sort of things that make them perform –– where you can push the boundaries and where youhave to tread carefully.

Those are the boundaries we’ve sought to explorewith this supplement. With the help of our sponsors,we’ve looked at a number of situations where theactions growers take, and the decisions they make,directly affect the soil.

Min till, for example, is one of the biggest soil-related changes many growers have made in thepast decade or so. It offers a proven benefit for soilerosion, but good weed control is key, for which aneffective stale seedbed is the cornerstone (p4).

But many growers are now making a return to theplough, especially where grassweeds are a problem.

It’s a skilled job, and many farms may have lost thistalent with the switch to min till, or need a refresher. So we’ve asked an expert for the key points (p12) anddrawn on the experiences of a Downland farmer who’sswitching the other way, into min till (p14).

Where tyre touches land is where growers can havetheir biggest effect on the soil, however. So we’velooked in depth at compaction, and how tyre set-upaffects this (p9). We’ve also found out from a Leicsgrower the decisions he went through when searchingfor the right tractor for his steep slopes and heavy soils (p6).

These are the tools through which growers forgetheir friendship with their soils, and when it workswell, the outcome is a crop that can fight throughadverse conditions and bring you a stonking yield –– dependable, supportive, reliable. I think it’s time I gave John a call.

Tom Allen-Stevens has a 170ha arable farm in Oxon, and is wondering how trundling all over hissoft and sodden land at harvest time is going to testhis soil [email protected]

Are you friends with your soil?

2 cpm magazine soil matters

Talking TilthA word from the editor.

A green bridge to soil benefitsNon-inversion tillage systems can reduce soil erosion and run-off, but effective weed control in the inter-cropperiod is essential for success.

Might and manoeuvrability A move to a high-horsepower wheeled tractor hasenabled one Leics farmer to alleviate headland compaction issues, save fuel and improve establishment.

Take the pressure offCrops that have to fight their way through over-compacted soils are highly unlikely to perform well. CPM seeks some expert advice.

Plough still key to controlling weedsRotational ploughing can play an important role in an integrated weed management programme by burying seeds and providing a clean start.

Stepping out of the furrowHaving a varied rotation across his Downland farm is helping one Berks grower bring in a more flexibleapproach to cultivations.

Special CPM Supplement

August 20122

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Editorial & Advertising SalesWhite House Barn, Hanwood, Shrewsbury,Shropshire. SY5 8LP

Tel: (01743) 861122E-mail:[email protected]

[email protected]

Advertising CopyBrooks Design, 24 Claremont Hill, Shrewsbury, Shropshire. SY1 1RD

Tel: (01743) 244403E-mail: [email protected]

CPM Editorial, advertising and sales offices are at White House Barn, Hanwood, Shrewsbury SY5 8LP. Tel: (01743) 861122. CPM is published ten times a year by CPM Ltd and is available free of charge to qualifying farmers

and farm managers in the United Kingdom.

In no way does CPM Ltd endorse, notarise or concur with any of the advice, recommendations or prescriptions reported in the magazine. If you are unsure about which recommendations to follow, please consult a professional agronomist. Always read the label.

Use pesticides safely. CPM Ltd is not responsible for loss or damage to any unsolicited material, including photographs.

Editor Tom Allen-Stevens

Sub Editor Charlotte Lord

Writers Tom Allen-StevensEmily PadfieldMick Roberts

Design and Production Brooks Design

Publisher Angus McKirdy

The key consideration is

not to compromise yourweed control. The easiestway to ensure this is with

an effective staleseedbed.


A 1999 survey of UK arable farmersfound that just 7% were practising min-till techniques to establish theircrops, according to ConservationAgriculture in Europe. Seven years later,the same survey revealed this had grownto 46%.

Over the same period, farm profitability figures suggest that shrinking arable margins were the motivefor most to abandon the plough. But how many

A green bridge to soil benefitsNon-inversion tillage systems can reduce soil erosion and run-off, but effective weed control in the inter-cropperiod is essential for success. CPM picks up some tips on achieving a good stale seedbed.

By Tom Allen-Stevens

growers have adapted their system to manage weedseffectively, and have they been making the most use ofthe potential benefits for the soil?

“Stale seedbeds have been a key part of the solution for the move from plough-based systems to min till,” says Alastair Leake, who’s been leadingsoil-related research at the Allerton Project atLoddington, Leics, and was formerly with the SoilManagement Initiative, that advised farmers on howbest to manage a change in cultivation technique.

“The ban on burning straw meant growers had tofocus on encouraging weed seeds to chit as soon as possible after harvest before spraying them off with glyphosate.”

Initially, light cultivation was seen as the route to encourage this. The principle is to keep the weedseeds near the surface, he explains –– blackgrassneeds exposure to light and germinates best in firm,moist soil, for example.

“But growers soon discovered that post-harvestcultivations left the surface a bit rough and didn’tencourage a chit, especially in dry conditions. Theessential element was to roll to keep the moisture in.”

Another problem was the cultivation kit available to growers in the early days of min till, recalls AlastairLeake. “Typically it would be a 3m cultivator drill thatwould loosen, seed and pack in one pass. But bigfarmers wanted to go wider, and often the pass wouldencourage a late flush of weeds that then had to betaken out within the crop.”

So effective weed control in non-inversion systemshas focused on very light cultivations following harvest, in the top 50-100mm, with the emphasis onconsolidation to achieve a chit. “Many growers havemoved to a system-disc, or similar drill, that justworks in a slot or disturbs the soil surface as little as possible.”

Challenges remain, such as how to achieve a good

“

”

5cpm magazine soil matters

Stale seedbeds have been a key part of thesolution for the move from plough-based systems to min till, says Alastair Leake.

Run-off trials at Loddington have demonstratedthe soil-related benefits of min till.

Mark Hemmant warns against going straight inafter harvest with a set of discs.

chit during very dry inter-crop periods, and how tomanage the straw, notes Alastair Leake. “Baling it isthe obvious solution for some, but this delays the startof your stale seedbed preparation. If chopped, it mustbe evenly spread and not too thick or this will hinderweed-seed germination.”

But min till also offers the opportunity to reducenutrient and pesticide loss to the environment througherosion and run-off –– 40% of UK farmland is deemedto be at risk, with an estimated 3M tonnes of sedimentwashed into rivers and drainage systems every year.

“Sediment washed off fields and through drainsoften carries with it nutrients, such as phosphorus, and residual herbicides. As well as being a costly lossof inputs, if growers can reduce the levels of thesedetected in water courses and drinking water, it’llreduce the threat of more onerous regulation, or worse,residual herbicides losing their approval for use.”

A number of studies have been carried out atLoddington to investigate this –– one of which waspart of the SOWAP (Soil and Water Protection) Project,a £4M EU Life study carried out in the UK and Europefrom 2004-07, co-funded by industry. It set out toexamine practical and economically viable solutions to soil erosion issues.

“We set up erosion tanks to monitor the sedimentand water volume that was washed off fields andthrough land drains in field-size ploughed and min-tilled plots. We looked at the effects of rainfallover the course of the season and brief, heavy rainfall events.”

The researchers expected the run-off to be greaterfrom the ploughed plots. “But at the start of the season, there was actually more from the min-till plots. Once the ground became saturated, however, theploughed plots then overtook the min-till plots, andthe sediment load from the min-till plots was alwaysless than that from the ploughed plots, even if the volume of water was greater.

“What was fascinating, though, was studying the soil biological activity of the min-tilled soil. There was asignificantly greater soil micro-biomass in this comparedwith the ploughed soil, and those soils prone to erosionhad less fungal hyphae. So the microbiological community helps to bind a soil together.”

A key concern in min till is surface run-off, whichhas come into focus in subsequent research, he continues. “We found you could reduce this by 50%with a simple uncropped margin at the edge of thefield. A tussocky grass margin would probably stemrun-off to water courses altogether in most situations.”

The studies have shown that non-inversion tillagesystems can provide both a financial and environmentalbenefit if managed right. “The key consideration is not to compromise your weed control. The easiest way to ensure this is to manage the weeds outside the cropping period with an effective stale seedbed,” notes Alastair Leake.

Achieving this has been the topic of some discussion at open days and demonstrations, notesMark Hemmant of Agrovista. “Going straight in afterharvest with a set of discs isn’t always the rightapproach. Instead, try to create a seedbed that bestmatches your target weed.

“Meadow, rye or soft brome need daylight to breaktheir dormancy, so are best left on the surface, but sterilebrome needs shallow cultivation or a good covering ofchopped straw. Blackgrass is a small seed, so needs to stay in the top 2cm, but importantly, you need to consolidate the seedbed to conserve moisture. For otherweeds and volunteers, going in quick after harvest withlight cultivations will encourage a good chit.”

Avoid heavy discs, he advises, as these will tend to bury weed seeds too deep and leave some weedsbeyond control with contact herbicides. “You want toapply the glyphosate as soon as you’ve a good initialflush. Try to repeat this two or three times in the inter-crop period, but if sticking to the same brand,make sure the product label allows for repeat doses.”

Glyphosate applied to stubbles is “fairly tolerant” to application technique, says Mark Hemmant. “Air-inclusion nozzles appear to work as well as flat-fan types. 100 l/ha is a good water volume to use,and best results can be achieved through spraying in theearly morning. You do need to watch for drift, however.”

Here adjuvants can help, he points out –– Agrovistafungicide efficacy trials have shown Companion Goldhave improved results when using flat-fan nozzles at a1m boom height. “Those in hard water areas may needto add a softening agent, and rainfastness of some formulations can be improved by adding a wetter.”

As the target weed is usually an annual seedling, a relatively low rate is all that’s required, he advises.“Volunteer potatoes and thistles are best targeted in the standing crop with a higher application rate.Rhizomatous weeds, such as couch, need a formulation

and rate that will translocate around the plant before itacts, so a quick knock-down formulation should beavoided where these are a target.”

Recent work carried out at Rothamsted Researchsuggests glyphosate rates need to be kept relativelyrobust for sterile brome. “We’ve found the recommendedrate of 1.5 l/ha for some formulations can be a little on the edge for bromes,” comments Rothamsted’s Dr Stephen Moss.

“There’s a steep response when you start to uselower rates, and poor results at a half rate aren’t unusual–– there’s good reason to stick to full recommendedrates, even if the target weed is small.”

He points out that sterile brome is a hairy grassweed. “I suspect that’s part of the issue. Gettingmaximum control from glyphosate is especially important where there are no follow-up cultivations togive additional control, such as when direct drilling.It’s in these situations that damaged plants are morelikely to recover.”

Other weeds that can be harder to control in stubbles include cranesbill, perennial bindweed andknotgrass, he notes. “Some polygonums can be tricky,but we’re not sure why –– it may be the way the activeis translocated through the plant.”

Broadleaf weeds are a particular strength forNufarm’s new glyphosate formulation, Rattler, accordingto the company’s Dick Dyason. “In independent trials itseems to be giving better control of broadleaf weeds,especially in stubbles.”

He attributes this to the “advanced” salt formulation.“Glyphosate is formulated with a salt, such as isopropylamine (IPA) or potassium, to help it get into the plant. Rattler uniquely contains both IPA and potassium. It’s been found to perform better thanthe sum of the salts used individually.”

Growers should note it’s a 540g/l formulation.“This means less product is required for the sameamount of active ingredient, which also means lesspackaging and potential time savings, when spraying.The product’s formulated with a high-quality tallowamine-type surfactant,” he adds. n

You need to have a tractor that'llconsistently pull the

drill, regardless of slopeor conditions.”

“


Steep slopes and heavy clay mean gettingcrops established can be challenging onAndrew Wheeler’s 500ha arable farm nearMarket Harborough in Leics.

One of the biggest challenges is the topography of the farm, he explains. “Steep hills can be a nightmarehere. In some places we’ve had to work downhill in the past simply because it’s too difficult to pull the cultivator uphill.

The arable rotation is broadly one-third oilseed rapewith first and second wheat. Most of the farm is on heavyHanslope clay, but there is a little ironstone on somereclaimed land. “We have to be flexible, given the soiltype,” he adds. “We may have to reintroduce spring cropsdepending on the blackgrass burden.”

In 2000 the Wheelers moved from a plough-based system to min-till. “We opted for a Claas Challenger with a Simba Freeflow drill, and cultivated using a Gregoire Besson Discordon.”

Might and manoeuvrabilityA move to a high-horsepower wheeled tractor has enabled oneLeics farmer to alleviateheadland compactionissues, save fuel andimprove establishment.

Emily Padfield

Although the system itself worked to establish crops,using tracks on the headland resulted in tremendouscompaction problems where the machine had turned,explains Andrew Wheeler. Then in 2005, he bought hisbrother’s share of the business and the farm was slightlydownsized. This allowed the Wheelers to revisit the trackversus tyres debate and they opted for a wheeled tractor.

His son James undertakes most of the drilling work,which amounts to 1011ha in total, with 500ha in-hand and the rest contract drilled for neighbouring farmers.

Initially, they used a John Deere 6920 to pull a SimbaXpress, while a Kverneland TS tine drill put in the cereals.Oilseed rape was planted using the Xpress fitted with aseeder unit.

“We found it was difficult to control the blackgrassusing this technique because of how much soil was beingdisturbed. All in all, I wasn’t completely happy with thejob the TS drill was doing. So I left James in charge offinding an alternative drill to suit our system. There werea few stipulations though.

“It had to be fully mounted, and I didn’t want anywheels. We knew what we didn’t want, but didn’t exactly know what we did.”

After a visit to Cereals in 2007, the Wheeler’s began totake an interest in the Claydon drill and went to see it inaction on a couple of existing users farms. It took a couple of years to be fully convinced, but they finally tookdelivery of a Claydon 4m Hybrid ahead of the 2010drilling season. In the first year the farm’s existing JD7830 pulled it, however it soon became obvious that theyneeded more than 200hp to pull the drill up the hills.

The redesigned armrest, or SideWinder II, hasmigrated up the New Holland range.

“I’ve no doubt that, on flat land, 200hp would be fine–– but on our slopes we needed more. Added to that wasthe fact we knew we wanted to expand and build our contracting acreage.

“We looked at Case IH, John Deere and Fendt and hada couple on demonstration, all around the 350hp mark.Everyone was telling us something different about thenew engine technologies available and we had alreadyhad some issues with the fuel in the 6920,” says Andrew Wheeler.

“We actively wanted something that worked onAdBlue. It made sense to clean up the exhaust gases in the exhaust and I didn’t think it entirely sensible to try to deal with exhaust gases in the engine.”

So they eventually opted for a New Holland, and therewere three main reasons, Andrew Wheeler explains. “We wanted to go to at least 350hp as we knew we wereupgrading the Claydon to a 6m machine. When we sawthe T8.390 in the yard at Turney’s –– our local dealer ––we knew it was a bit bigger than we wanted but it wasfully specced with everything we needed, so we went for it.”

The relationship with the dealer was also important, aswas the three-year warranty, he adds. “He was the onlysalesman to sell on the kit’s merit and not on the downsides of competitive machines.” s

In 1994, New Holland turned a bit of a cornerwith a concept on the 70 Series (or Genesis).Boasting SuperSteer, which reduced turning circles by nearly 40%, the 70 Series was thefirst in a move by the big tractor manufacturersto produce a long-wheel base, 200hp+ machinethat allowed operators to turn tightly enough onthe headlands. John Deere launched the 8000Series in 1996 and Case IH came up with theMX Magnum in 1997.

Over time, manufacturers went down tworoutes with tractors over 200hp. One was a row-crop tractor suited to drawbar work, like theJohn Deere and the Case IH, and the other wasthe more universal, European-bred compacthigh-hp tractor, like the Fendt Vario, the MF8400 and the New Holland T8000.

The latter were compact in design, but had a longer wheelbase to give better stability on theroad, and were lighter, with the possibility ofweight being added. Integrated front linkagesand front PTOs also became more common.

For whatever reason, the T8000 wasn’t initially a runaway success for New Holland,despite meeting most of the needs of a compacthigh-hp tractor. Common complaints included a need for a reversible fan, no combination ofSuperSteer and suspended axle and no powerboost. So, in a bid to regain the popularity of

the 70 Series of nearly 20 years previously,New Holland started asking customers what they wanted from the new T8.

Above all, the overarching request was for a tractor that minimised soil damage and hadgood manoeuvrability. With this came the development of the T8 series, with a new cooling pack, suspended front axle, longerwheelbase and optional cab suspension.

By adapting the suspension system andlengthening the wheelbase, the new T8 is now capable of putting more power to theground more comfortably for the operator,says New Holland.


At a glance: New Holland T8.390 UltraCommandPower (boost) 340 Rated, 373hp (389hp)

Engine FPT 9-litre Cursor 9

Transmission 19F/4R 50kph or 23F/6R 40kph with Creep

Hydraulics 163 litres/min option of Megaflow at 274Litres/min

Linkage lift Rear: 10.2t Front: 5.8t

Turning circle 4.97m

Weight 11.3t

Service interval 600h

Price £165,561

Andrew (left) and James Wheeler were lookingfor a tractor that combined plenty of horsepowerwith flexibility of use.

The Wheelers opted for a Uniglide hitch, that hasno lift rods and offers better visibility.

Because James Wheeler spends the winter abroad asa qualified ski instructor, the farm is geared up to run as a one-man operation at certain times of the year. “That’swhat makes it so important to have a wheeled tractorcapable of being put on a number of different jobs. It’sjust about sensible to be used for jobs like corn carting if there’s a problem with another tractor.”

The ability to fit and unfit weights quickly to theT8.390 means it doesn’t take long to change task fromdrilling to straw raking if the need arises. Currently, thereare Michelin 800s fitted to the rear with 2t wheel weightsand a 1.5t front block.

Powered by a six-cylinder 9-litre FPT Cursor engine,the T8.390 has a maximum rating of 389hp with powerboost. Maximum torque is measured at 1500rpm at 1671Nm.

The father and son team has opted for a BennetEngineering Uniglide hitch, instead of that offered asstandard from New Holland. With no lift rods and a vastlyimproved visibility, the hitch is said to be more reliableand wear is kept to a minimum.

“For a heavy-mounted implement like the Claydon,you need the length and power to be able to pull it, especially on our land. Because it has a small coolingpack and the bonnet is sculpted, you’re able to turn on a sixpence and, when we’ve happened to put it on a dumptrailer, the turning circle is surprisingly tight.”

And this is despite the lack of SuperSteer (see panel)in the new range.

“We also find the linkage to be far superior to whatwe’ve had before. Our older tractors used to eat linkages,but because this one is heavier duty it copes far better.”

The T8 is equipped with New Holland’s Ground SpeedManagement (GSM) feature, which allows the driver toselect a speed and then it matches the correct gear to this,regardless of the task in hand. “I drive it all the time inGSM mode –– it’s just like having a Vario but without thepower loss,” explains James Wheeler.

“When I’m drilling I can set it at 11-12km/h and itmatches it, whether we’re going up or downhill. When thedrill is also your primary cultivator, you need to have atractor that’ll consistently pull it, regardless of the slope or conditions, and the T8 manages that perfectly.”

Having GSM does mean that when drilling, the tractorhas been using in the region of 11-12 l/ha of fuel. “We’vefound that AdBlue usage is roughly one tank to threediesel fill-ups. When it’s working hard, it uses in theregion of 1.4 l/hr of AdBlue.”

In the cab, the redesigned armrest, or SideWinder II,

Concerning turning

The new T8 can put more power to the ground,says New Holland.

which has migrated up the New Holland range, meansthat most everyday controls are located on a joystick. “It’s so handy having forward and reverse on the joystickand the two programmable buttons mean you can set ithow you want it to be.”

Additions like Xenon lights mean James can continuedrilling through the night, also aided by New HollandIntelliSteer and OmniStar GPS.

“Mechanically, there’s not a lot I don’t like about thetractor. In fact, the only thing I would change is that thescreen could be a bit bigger for setting up the GPS andheadland management system.

“There’s no doubt that, working in a straight line withan implement on the drawbar, nothing can beat the draftof a crawler machine. But in our situation, where the landis so heavy and there are a lot of hills, the New Hollandhas been phenomenal.” n

s


Take the pressure off

Crops that have to fight their way through over-compacted

soils are highly unlikely to perform well. CPM seeks

some expert advice.


It takes no time at all to

compact a soil, but it can take years torepair the damage

done.

“

”

Over-compacted soil can be one of themain reasons a crop fails to yield to its

full potential. But it’s also one of the mostmanageable, according to experts. There can also often be a thin line

between what constitutes good and poor management, with much

depending on the nature of the soil and conditions at the time.This year, as autumn cultivations get

underway, the potential for damage from travelling over your fields may be much

higher than usual, warns Tim Chamen of Controlled Traffic Farming –– high soil

moisture raises the risk significantly. So getting the fundamentals right

–– correct tractor balance and tyre

pressure, for instance –– are more important than ever,maintains Barry Coleman of Firestone, who flags updevelopments in tyre technology that can also help.

What is over-compaction?Tim Chamen: Over-compaction is where a soil’s function has diminished because it has fewer pores that

contribute less to its structure. A firm but well structuredsoil will aid rooting and increase the amount of plant-available water, but this will be limited in an over-compacted soil.

It will also tend to hinder rooting –– plant roots mayonly be able to forge a passage through the soil’s naturalfissures, so will be underdeveloped and stunted wherethese fissures are few and far between. Then, when the soil dries up, both available moisture and a plant’s abilityto draw on it become severely restricted.

Compaction can be localised or widespread within afield. It can occur in a layer –– close to the surface or atdepth –– which will hinder rooting and water movementabove or below. A soil’s ability to resist over-consolidationwill depend largely on the forces exerted on it and its natural structure. It will also depend on the soil type andorganic matter content, while conditions on the day willdictate how pliable the soil is, and therefore how prone itis to damage.

What causes it?TC: The main cause of compaction is machinery travelling over the soil. In a typical season, between 30-100% of the surface of the average arable field will be driven over by vehicle tyres at least once. As arablemachinery gets larger, the forces exerted through tyres arepotentially greater and reach to a greater depth –– thepressure in the soil drops to approximately half of the tyre pressure at a depth equal to the tyre width.

It takes no time at all to compact a soil, but it can takeyears to repair the damage done. Where there’s randomtraffic movement over a field, there’s a much greaterchance most of the field will become over-compacted in just a few years.

Another cause is smearing –– a sheering of the soilthat seals it up, creating an impenetrable layer. This iscommonly caused when soils are wet, often by cultivationdiscs, but also through wheel slip of tractor tyres.

A plough pan is a compacted layer created at thedepth of the plough, but it isn’t caused by ploughing –– the action of the plough generally leaves the land in agood condition and the soil can heave upwards under theplough, aiding its structure at depth. The pan is generallycaused by the tractor wheels in the furrow, pressing onthe fresh, exposed soil. The tractor itself is also tilted,putting more weight on the tyres in the furrow.

What are the costs of compaction?TC: The costs are numerous, ranging from higher fueluse for tillage, lower crop yields (8-12% for grain crops)and poorer fertiliser use efficiency.

The damage to crops is often evident above ground,with compaction causing stress due to water-logging inwinter and drought in summer. With more limited rootgrowth, crops are also unable to access nutrients, whichall put a severe dent in the final yield.

Compacted soils are harder to work –– it can take upto 60% extra draft to cultivate a soil that’s compacted to10cm depth, compared with one that’s well structured,and an extra 20% for ploughing at a depth of 20cm to

An over-compacted soil will hinder water and nutrient availability to the crop, says Tim Chamen.

s

A tractor with fully mounted plough has been weighed, with each rear tyre carrying5640kg. A choice of tyres is given below:Tyre Max weight (kg)* Pressure @5640kg Comments

– bar (psi)*

*Recommended values for road travel @50km/h

Trying tyres

Up to 100% of the surface of the average arablefield will be driven over at least once in a season.

Barry Coleman points out that running tyres at the wrong pressure is the single biggestpreventable cause of compaction.

remove compaction. This puts up overall fuel costsand increases the horsepower needed to create a seedbed.

There are also considerable environmental costs. Low water infiltration in compacted soils leads to greaterrun-off, causing erosion, pollution and increasing thelikelihood of flash floods. Recent work has shown thatfertiliser use efficiency is also reduced. If more than 60% of a soil’s pores are filled with water, applied nitrate fertiliser will often convert to nitrous oxide –– a damaging greenhouse gas.

What soils are vulnerable?TC: All soils are prone to compaction, from light sands,through fine silts to heavy clays. A good organic mattercontent can therefore help their resilience as the fibrousparticles build structure, maintaining pore size and helping to dissipate applied forces.

The more you work a soil, generally, the more vulnerable it is. An undisturbed soil tends to have a betterstructure, with stable pores that can carry the tractor’sweight better. Over-working a soil destroys these naturalpores and depletes organic matter, making it even morevulnerable to erosion.

Soil moisture has a huge influence on whether theland is prone to over-compaction –– a resilient soil canturn high risk with just a few mm of rain. There are nohard-and-fast rules here –– a good knowledge of yoursoils and experience are the only ways to tell.

How can you reduce over-compaction?Barry Coleman: The single biggest preventable causeof compaction is running tyres at the wrong pressure. The pressure in your tyre directly relates to the pressure

you exert on your soil. You want to aim for as low a pressure as possible in the field, while ensuring the tyre doesn’t slip on the rim.

The forces exerted on the soil at depth relate to thefootprint of the tyre and the load, with the pressure at thesoil’s surface the same as the inflation pressure. Usingwider tyres at a lower inflation pressure will therefore dramatically reduce compaction, and increase traction.

Excess wheel slip is usually the result of poor set-up,over-inflation or operation and you should aim for a slipratio of no more than 8-12%. Wheel slip is often causedby worn tyres, or a mismatched or unbalanced tractor forthe job. A high forward speed can also cause wheel slip.

How do you set up a tractor and its tyres to minimise compaction?BC: First, you need to put the tractor in a work configuration and weigh each axle. For field work, yougenerally want to balance the tractor, using weights orballast, so 40% of the weight is carried at the front and60% at the back. When measuring axle weight, bear in mind if you’re ploughing that more of the tractor’sweight will be transferred to the wheels in the furrow, so you may want to use blocks to simulate the actualworking weights.

In order to run at a low pressure, try to choose thebiggest tyre you can practically fit to the tractor. A typicalfront tyre size, for example, is 420/85 R28, where the section width at nominal pressure and load is 420mm,the height of the sidewall is 85% of the section width and the wheel rim diameter is 28in.

Each manufacturer produces tables you can use tolook up the correct inflation pressure. For Firestone tyres,there’s a smartphone app, available to download for both iPhone and Android handsets, that points you conveniently to the correct pressure for the job (www.firestonefarm.eu/apps).

How can tyre technology help?BC: The difficulty when setting tyre pressures comeswhere road travel is involved. Generally, the correct pressure for field work would be lower than for safe roadtravel at 50km/h. As it’s difficult to adjust pressure in thefield, most operators tend to compromise, setting a pressure that’s above the ideal for field work, while causingextra wear and damage on the road at high speed.

To overcome these problems, some tyre manufacturersnow supply Increased Flexibility (IF) tyres. With an IFtyre, the load that you can safely carry at speed on a lowpressure is dramatically increased. This is thanks to a new design of sidewall casing that makes the tyrestronger and more flexible. This means you can set IFtyre pressures in the yard for field work, safe in theknowledge that they’ll also resist the heat build-up at high speeds (see panel).

How do you alleviate compaction?Tim Chamen: The first thing to establish is where in the field you have it, and to what depth. While a soil penetrometer gives you a numerical reading, an ordinarygarden fork makes a suitable alternative to around 30cmdepth once you know what you’re looking for. Where youfind a hard layer, dig it up –– over-consolidated soil willhave a platey, tighter structure and will often look quitedifferent from the soil above and below it.

However you choose to cultivate to loosen the soil –– through sub-soiling, ploughing, etc –– the crucialelement is to decide how you are then going to stop thearea compacting again. With just two passes over freshlyloosened soil, you can return it to its former state orworse, so light, low-pressure or controlled traffic are theobvious long-term solutions. Controlled traffic can reducethe compacted area of your field to as little as 15%. For more, go to www.controlledtrafficfarming.com n


s

650/65 R42

710/70 R42 Standard

710/70 R42IF

4250

6500

77507750

-

2.0 (29)

1.4 (20)1.4 (20)

Tyre is overloaded and potentially dangerous @50km/hSafe to travel, but could cause compaction

Less compaction and betterfuel economy

IF tyres allow for safe road travel at lower pressure.

Plough still key to controlling weeds

As the battle against rising weed populationsintensifies, the focus of the fight is shiftingmore towards cultural control methods, andestablishment regimes are having a rethink.Faced with escalating problems and herbicideresistance, more growers are now turning tothe plough to provide a fresh start.

Blackgrass is the major issue –– a by-product ofmore autumn-sown crops, earlier sowing and a wideradoption of minimum tillage, says Dr Stephen Moss, of Rothamsted Research. “Blackgrass plants can onlyemerge from seeds retained in the top 50mm of the soil.Provided there’s sufficient moisture, at least 80% of thetotal germination and emergence will occur between Septand Nov.

“So even where stale seedbeds and total herbicidesprays, such as glyphosate, are used before drilling, mostcrops will have been sown before much of the blackgrasshas emerged. And because the seed will only germinatein the top 50mm, the potential for weed populations toincrease is much higher in min-till and direct-drillingregimes,” he explains.

Ploughing, however, is proven to provide effectivecontrol, particularly in rotation with other implements.This is because, if seeds are buried below the crucial50mm layer, or preferably deeper, they’ll decline at a rateof 70-80%/yr. “So after three years only about 3% of theoriginally buried seeds will remain viable. But this can

still be a considerable number of seeds.“There is an argument against ploughing that says

‘you’re continually bringing up old seeds’. But thisignores that you’re often also burying a lot more newlyshed seeds at the same time. There needs to be a balance between the amount of new seed buried and theamount of old seed ploughed up. That’s why rotationalploughing –– once every four to six years is the optimum–– is an effective way of controlling grass weeds, especially blackgrass. It provides a fresh start, with shallower cultivations in following years ensuring weedsaren’t brought back up into the 50mm zone on the surfacewhere they can germinate,” he says.

At the same time, Stephen Moss suggests this is alsoan opportunity to put more thought into the crop rotation.What’s profitable in the short term, he says, may not besustainable over longer periods. Continuous autumncropping may well not be sustainable on heavy land withbad grassweed problems. “There’s a need to add somespring cropping into the mix to provide more time totackle weeds,” he adds.

Even with rotational ploughing, a small proportion of seeds will remain viable. If these dormant seeds arebrought back up to the surface a high proportion will germinate given favourable conditions and the cycle willcontinue,” he says. “Autumn ploughing once in every sixyears before a spring crop –– such as beans –– providesfarms with a lot of time to control blackgrass beforespring sowing.”

However, he warns, intensive cultivations and earlysowing can still result in substantial infestations in springcrops, so it’s no miracle cure.

David Rose, of Kuhn Farm Machinery, says the


Rotational ploughing can play an important role in

an integrated weed management programme

by burying seeds and providing a clean start.

By Mick Roberts

Even where stale seedbeds are used before drilling,

most crops will have beensown before much of

the blackgrass has emerged.

“

”

To achieve good weed control with the plough,set the skim coulters to slice off the top 50mm and ensure the furrow closes over the top.

need to turn the soil quickly to establish crops couldmean current commercial ploughing methods may be too fast for effective weed seed burial. “As with allimplements, it’s important to plough at the correct speed to accomplish the desired result, which in this case is to bury the trash and close the furrow to prevent light reaching the weed seeds,” he adds.

But there’s a fair amount of setting and adjusting theplough to do before starting work, he adds. “Ploughing to control weeds is a different job to perhaps operatorshave been doing recently, which may have been more targeted to turning over the ground as fast as possible. In that case, they may also have been aiming to break upthe furrows, which is not what’s required to bury weeds.”

While there are many different types of plough, in theUK Kuhn sells just three –– standard, wider and slatted.

All modern mouldboard designs, says David Rose, arecapable of producing good quality work and will effectively bury seeds when the plough is set correctly. “A slatted board is more suited to ‘sticky’ and peat soils.And this will produce a more broken finish comparedwith a full board. Otherwise choose the mouldboards tosuit the tractor –– with the wider ones for bigger tyres,”he says.

Good maintenance begins at the end of the previousseason, protecting the mouldboards and lubricating allthe main components. This is to ensure that they don’tseize-up during storage and can still be used to make thenecessary adjustments. Similarly wearing metal needs tobe replaced, not only to protect the plough’s structure, butalso to ensure it works well –– new points, for example,help it to penetrate.

“Then look at the manual and check out what adjustments can be made in the yard. On Kuhn ploughsit’s possible to pre-set the correct beam alignment to thetractor’s track width. There are measurements on thebeam that correspond with the width between the innertyre walls.”

The tractor lift rods on the linkage arms should be set to the same height; and adjust the check-chains toprovide about 50-75mm of movement, so the ploughfinds its own line in the ground.

When adjusting the plough on the tractor, consider itas being set in a square, looking from the back, and arectangle from the side, suggests David Rose. “Lookingfrom the rear, the plough should be upright and at 90° tothe ground. From the side, the beam should be parallel tothe ground, so it’s at the same depth from front to back.”

Another key setting is the front furrow width. Once thishas been set for the plough and tractor’s track width it’s not usually necessary to change it again. If it’s too wide ornarrow, it’ll result in uneven work, which is easy to spotfrom the discernible bout patterns and, sometimes, tufts of trash between each set of furrows.

Survival of buried blackgrass seed in the soil is about 20-30%/yr, says Stephen Moss.

It’s crucial to operate the plough at the right speed for the job and to keep checking the work says David Rose.

Ten top ploughing tips

1. Keep the plough well maintained and ensure parts are lubricated to make adjustments easy.

2. Check all wearing parts and replace if necessary.3. Ensure tractors tyres are inflated to correct

pressures and are equal both sides.4. Read the manual and make as many adjustments

as possible in the yard.5. Adjust the plough so it’s vertical and the beam

horizontal when in work.6. Mark the headland for neat and tidy ‘ins and outs’.7. Set the skimmers to the correct depth – remove

just the top 50mm.8. Set forward speed for a smooth flow of trash into

the furrow to be buried.9. Make only one adjustment at a time, travel a little

distance and check again.10. Get off the tractor seat – keep a regular check on

the work.

Working depth is set on the tractor’s link arms and therear depth wheel –– the aim is to adjust these to keep theplough horizontal across its length. “On a tractor withlower-link sensing, the top link should be fitted into theelongated hole. Use the fixed hole on, usually, older tractors with top-link sensing.

“A good indicator that the plough is set up correctly isthat the top link is pulling straight. If the plough ‘crabs’ toone side then some basics need checking –– for exampleincorrect alignment to wheel track width,” he adds.

The need to bury the weed seeds calls for careful attention to the skim coulter settings. These should be setto cut 50mm deep. “The idea is to cut a clean slice off thetop corner of the furrow as it’s turning and deposit this inthe furrow bottom, with the furrow landing on top. It’simportant not to take off too much soil, so the furrow closes over the top,” says David Rose. “Speed of operationis crucial: it needs to be maintained just right so there is a smooth flow of residue into the furrow bottom, and toallow the furrow to fold over on top and not break up.Remember, this is the only tool available to create a completely clean start.”

Before starting work, however, it’s important to mark outthe field, he concludes. “This keeps the ‘ins and outs’ evenaround the headland and results in a better, neat and tidyjob. Make the headland wide enough to easily carry out afull turn, but be careful the last run around the field doesn’tend up with the finish in the tramline wheel mark.” n


Stepping out ofthe furrowWhile many growers may now be rediscoveringa use for the plough after years devoted to mintill, John Maxted is doing quite the opposite.Until two years ago, all the arable land on hisrolling Downland farm between Newbury andOxford in Berks was ploughed in front of everycrop. But last year, he introduced min till intothe rotation.


It’s important not to go too deep,

but essential to buryeverything.

“

”

“You could call me an old-fashioned cocker but Ilike to bury the rubbish –– it’s against my upbringingto see trash on the surface,” he says.

Yet across the UK, problems with blackgrass control have arguably brought this view back in vogue. Burying the weed cleanly is one of the optionsrecommended to regain control where grassweedshave taken over –– a point not lost on John Maxted.

“Those who’ve previously been 100% min till arenow finding they’re having to go down the inversiontillage route occasionally. In the past, there may havebeen less requirement to bury the trash because of themachinery and chemistry we’ve been using. But now,

we know we’ve all got to do more to help ourselves.You need to move to a combination of different agronomic tactics –– stale seedbed, ploughing and min till.”

Grassweeds haven’t yet been a huge problemacross Maxted Farms’ cropped area –– 700ha ofDownland chalk outcrop, topped with “classic” claycaps. “I’m seeing more blackgrass and sterile brome,and suspect we may even have resistance. It’s notaffecting our yields as yet, but I don’t like to see it.We’re trying to adopt a different approach in each year,with different crops and different cultivations.”

Spread of croppingWith the introduction of min till, the ploughed area hasdropped to around 75% of the total, with cultivationstailored more closely to the crop type. A spread ofcropping sees wheat rotated around oilseed rape,beans, oats, spring and winter barley, and JohnMaxted aims to introduce one new variety on to thefarm each year.

The spring barley –– currently 100ha of Propino,following many years of Tipple –– could be consideredthe farm’s most successful crop. “We grow a decentmalting barley –– the Downs is traditional spring barley land. Last year, our crop was entered into thebest barley competition and won.”

The plough –– an 8f Kuhn semi-mounted ––continues to prepare the land before spring barley.Maxted Farms follows an uncomplicated and provencultivation regime that sees the stubble sprayed off infront of the plough, which is followed by an 8m Dal-BoCultimax spring-tined cultivator.

“It’s easily ploughed land, and we’re only going to a depth of about 175-200mm. It may cost more toplough and tiddle the top in front of the drill, but it’snot as much as some people maintain.”

A 6m Kuhn Megant 600 tine drill completes theestablishment picture. “It’s one of the few drills that’sall things to all men, working quite happily in a conventional system or on min-tilled land. We’re also careful on our soil not to go too deep as it’ll bring up flints.”

The policy is always to plough after the oats to burythe straw. This year, there’s 57ha of Gerald, sold toQuaker and Morning Foods. “In gross margin terms,oats performed best last year, mainly because I hit the

Having a varied rotation acrosshis Downland farm is helpingone Berks grower bring in a more flexible approach to cultivations.


Flints in the soil cause excessive tyre wear – landwheels are foam-filled.

Steep slopes on his Downland farm mean JohnMaxted is reluctant to invest in cultivation kit thatrequires a lot of horsepower.

market right. The downside of the crop is that you can’ttake blackgrass out.”

This makes it “tricky” where oats follow wheat, soit’s one place in the rotation where the min-till strategyis being tried. “We’re trying to encourage a carpet ofweeds that’s then taken out with glyphosate in front ofthe drill –– the plough isn’t used at all in this situation.”

This year’s 300ha wheat portfolio comprisesEinstein, Cordiale, Scout and Santiago. “The ground’snot good enough for a Group 1 miller, but Cordialegets a good premium –– if you strike it lucky, it canbe within £5/t of a Group 1. Einstein can make a premium, too, while Scout is a banker –– a good variety that can bring us 10t/ha. Santiago tillered likecrazy and put on plenty of growth, so we’ll see if ityields at harvest.”

Most of the wheat is preceded by the plough, withland coming out of winter beans ploughed “to pull itdown flat”, says John Maxted. Traditionally, the 61haof winter beans have been established using a hired-indeep cultivator. But this year, three different systemshave been tried, including the plough and the farm’snew Simba 3m DTX cultivator.

“All of the beans look extremely good this year,although I worry about the level of pod set. However,we’re now looking to drop the crop in favour of OSR.It’s been a wonderful break, but at just 5t/ha, you can’t extract as much from the market as you can forother crops.”

The OSR slots into the rotation no more than oneyear in four, and currently extends to 142ha of Sesame,Dimension and Expower. “I was absolutely cocksurethat I wasn’t going to plant a conventional varietyagain, and go with all hybrids. But the Expower’s goneflat and the Dimension doesn’t look too good. Only theSesame has survived the season unscathed.”

The aim with the OSR establishment is for one pass of the DTX in front of the drill, with any emerged

weeds sprayed off before drilling. So is the new regimeworking out?

“I can see min till has its place in terms of timeliness and it does offer a different option for weedcontrol. There are other benefits too –– our soils generally aren’t prone to compaction or pans, apartfrom the clay caps, where there’s an advantage in justtiddling the top to establish the crop. In dry years, I can see it can preserve moisture, although that’s not generally a problem on our chalk.

Soil disturbance“But with any establishment system, you need to use abit of nous –– in a wet autumn, the plough helps todry out the land quicker, for example. Also, to mymind, min till means minimum soil disturbance. If youend up making umpteen passes to establish a crop,you disturb the soil more and it costs you more thanploughing in the end.”

Horsepower requirement is another concern.Currently, the largest of the farm’s three main tractorsis a New Holland T8020, rated at 250hp. The farm hassome steep slopes and John Maxted is reluctant toadopt any cultivation kit that requires a lot of grunt atthe front.

“The downside of a lot of this min-till kit is that youneed a big tractor to pull it, using a lot of diesel. I trade tractors in fairly regularly, and I want to makethe best use of their fuel efficiency. I don’t want to be in a position where I have to have one tractor dedicated to cultivations –– the tractors should be available for any job, any day of the week.”

Adopting min till has meant a change of mind set,and John Maxted admits he was reluctant to departfrom an all-inversion tillage system –– “We felt weshould at least have a look at it.”

But the farm has retained the knowledge and experience to get a good result from the plough –– assets that many others have now lost. There arethree full-time staff, who between them have clockedup 61 years at Maxted Farms. John Maxted himself is currently bringing in his 52nd harvest, and countshimself “a true Downsman” who knows the limitationsof his soils.

“It’s important not to go too deep, but essential to bury everything,” he says. “You sometimes need to play around with the plough to get it right. It

doesn’t have to be competition standard as long aseverything’s buried. But getting the tractor balance andbasic set-up right is a given –– if you can’t get alongwithout controlling wheel slip, for example, youshouldn’t be doing the job. And you need to knowwhen the ground conditions aren’t suitable.”

The plough covers 20ha/day, and while the cultivation regime is still adapting to the introductionof min till, the spread of cropping and team disciplineensure the farm extracts the maximum benefits fromthe change. So what about those farms moving awayfrom 100% min till and reintroducing the plough?

“It’s an easy thing to get wrong. You need decent kit –– don’t just get the old rusty plough out of thenettles. Put a bit of thought into it, buy a reasonableplough and set it up right so it buries the rubbish ––there’s no magic to it. We’re going to find we rely moreand more on mechanical means to make an effectivestale seedbed. Those who don’t manage it right willleave a green bridge for grassweeds and foliar diseaseto take over.” n

Despite recently introducing min till into hiscultivation regime, the plough remains the maintool and is still best for preparing seedbeds formost crops, says John Maxted.

Maxted Farms, East Ilsley, nr Newbury, Berks

l Staff: Three full-time employees; contractor now used for grain cart only

l Combine: Claas Lexion 570+ with 9.1m header

l Tractors: New Holland T8020, 2x New Holland T7050, New Holland TM175

l Sprayer: Househam 3000-litre self-propelled with 24m boom

l Spreader: Kuhn Axis 30.1 with 2.5t hopper

l Drill: 6m Kuhn Megant 600

l Ploughs: 8f Kuhn semi-mounted,6f Kuhn mounted

l Cultivators: 3m Simba DTX 300,8m Dal-Bo Cultimax

l Handler: Manitou 633

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