TRAVEL LIGHTLY
TRAVEL LIGHTLY
With so many winter cropping plans disrupted this year, spring cropping will increase, or make a return, to many rotations. Peter Hill seeks advice from tillage consultant Steve Townsend.
WORK shallow and use as few passes as possible to prepare for drilling. Good advice at the best of times but particularly relevant in a year when many growers face the prospect of turning sodden, poorly weathered soils into acceptable seedbeds for spring-sown combinable crops.
The scenario will be different on almost every farm, depending on soil type, the amount of land destined for spring crops, and whether some autumn cultivation was achieved before the weather turned sour. But the principles remain the same, suggests Gloucestershire-based tillage systems consultant Steve Townsend.
"Check-out the depth of any weathering effect on ploughed, cultivated or stubble fields, and work any tillage equipment as far as possible within that depth," he suggests. "Also, be aware that the underlying soil will remain wet and vulnerable to compaction for some time. So the fewest possible passes with tractors equipped to give as light a tread as possible will help avoid doing any more damage."
As a former Monsanto business manager involved in the development of the ECOtillage approach to integrated weed control and cultivation, Mr Townsend remains a keen advocate of using the sprayer to tackle over-wintered weeds and minimum cultivation techniques, where appropriate, to establish crops.
"There is no quicker or cheaper way of controlling over-wintered weeds than putting on glyphosate," he insists. "And minimum tillage can have a big impact on costs simply by reducing the amount of field-work needed to establish a crop."
Reduced or minimal cultivation may not be appropriate for all spring cropping situations, he concedes. But it should still be possible – and certainly preferable given the delicate state of many fields – to either cut out passes or combine operations.
The primary objective will still be to produce an even, level seedbed, with a reasonably fine tilth for good seed/soil contact and sufficient moisture for germination. Light, free-draining land should present no great problems, although there is some danger of over-working the sandier and siltier soils, which tend to have a poor natural structure.
"But on anything heavier," warns Mr Townsend, "growers should take care in fields that took a hammering in wet harvest conditions or have poor structure due to waterlogging not to do any more harm."
That means taking advantage of any significant frosts to level ploughed or rough cultivated land while the ground is firm and supportive; not working deep enough to drag up wet, unweathered soil which then needs costly efforts to force a seedbed; getting the job done quickly when conditions allow and with fewest individual operations; and, on heavier ground particularly, using whatever means to minimise the compaction impact of tractors and implements.
KEEPING poorly structured soil beneath the surface and avoiding compaction will be two of the key aims on land ploughed late autumn, suggests Mr Townsend.
"The mild conditions weve experienced so far means there is not much depth of weathered soil on ground that has withstood the rain and a lot of ploughed land has simply slumped in the face of persistent, heavy rainfall," he notes. "We may yet get some helpful frosty weather but, as time goes on, it is clearly going to be quite a challenge to produce a seedbed in these conditions without dragging up wet, unweathered material from underneath."
Careful timing, taking advantage of frost-firmed conditions in fields that need levelling, and setting implements to work effectively but not too deep, will be necessary.
Given the likelihood that soils are going to remain wet for a time to come yet, it will pay to keep the weight off tractors and equip them with big tyres or dual wheels. Not only to guard against causing more than the usual amount of compaction but to limit the depth of wheelings that must then be taken out by setting cultivators deeper than perhaps they really need to be.
A spring tine cultivator will be the implement of choice for many in this situation, especially on ploughed and pressed ground that needs little levelling. Modern designs can be set to work shallow and consistently, and offer both wide working widths and a decent turn of speed to get through the workload.
On wet, heavy soils with proud furrows, the power harrow is likely to be a better bet as it will level and produce a near-finished if not finished tilth in one go at the expense of work rate of operating costs.
"Still, as an alternative to making several passes with other implements and using a separate conventional Suffolk-coulter drill, the cost and work rate penalties are probably worth it," he says.
Equally, there must be scope to use a disc or tine cultivator drill to good effect, as long as the soil is relatively firm and there is sufficient depth of weathered soil for the machine to create its own seedbed without much (if any) prior working.
MOST likely to have retained a decent soil structure by being less susceptible to seemingly endless heavy rain, disced stubbles will nonetheless dry relatively slowly.
"If time is pressing, light tine cultivation to draw the disced soil into ridges will help drying but be sure not to work any deeper," is Mr Townsends advice. "Otherwise," he adds, "patience is the watchword – avoid getting into a drilling race with your neighbour!"
First operation will likely be a dose of herbicide to clean up over-wintered weeds, followed by a choice of tillage techniques or, if conditions and sowing equipment allow, going straight in with the drill.
"If the ground was properly consolidated by pressing and/or rolling after the discs, chopped straw and stubble should have broken down reasonably well and not present too much of a problem," Mr Townsend suggests. "But there will also be more likelihood of capping on some soils, so its a matter of deciding whether the drill will take that out if nothing else is done first."
On disced stubbles that have weathered well, going straight in with a power harrow- or rotary tiller-plus-drill combination should be a distinct possibility in many situations, with the attraction that this will minimise travel over what should be decently firm soil.
But disc or tine drills should also be well-placed to tackle these conditions with minimal preceding work and, indeed, may need to be set with a less aggressive action in the case of those with cultivator ele-ments ahead of the coulters.
SLOWEST to dry and with the least depth of naturally weathered soil, tackling untouched stubbles is likely to be a case of extremes.
Ploughing, where this is demanded by the use of conventional Suffolk-coulter type drills; minimum tillage, as long as soils are easily worked and there is not too much surface trash; direct drilling, if surface trash is not excessive and soils are unlikely to smear.
"Direct drilling should certainly be considered for break crops if conditions and soil type are suitable, especially by growers faced with a heavy workload," argues Mr Townsend. "It is a big time and energy saver, and can spread the workload by involving a contractor. Its also the best way to preserve what little natural tilth is present."
Patience, again, will be an important element of the success of this approach, since soils must be allowed to dry sufficiently for the discs coulters to form a proper mini seedbed, not merely a smeared slot.
Where direct drilling is not an option, then minimum tillage is the next best thing, according to Mr Townsend, as long as implements are kept shallow. Tines and discs can be chosen for whichever is the most effective for the soils and conditions involved. But trash levels will be a consideration as there will clearly be little time (nor any desirability) for umpteen passes trying to incorporate it.
Ploughing has the attraction of leaving a clean surface for conventional drills but is slow and expensive by comparison. Soils still wet below the surface risk compaction from running down furrows, not to mention a smeared furrow bottom if traction is poor.
"But if ploughing is the chosen solution, consider turning suitable land if we get sufficient frost to firm things up, and work the plough narrow and shallow rather than turning up great slabs of soil that need energy and time breaking them down again," suggests Mr Townsend.