As tractors become more powerful, so subsoiling equipment is being made bigger and tougher to suit. Peter Hill outlines whats on offer.
Coil spring leg protection is optional on the 300-series Simba Flatliner, enabling continuous work in stony or extra heavy soils.
Farmrite Loosen It has a V-shaped toolbar to set the pivot mounted tines in a swept formation. Optional leading discs reduce surface heave.
Series 500 is the tougher, deeper version of two Flatliner models from Simba; this 3.5m model has five legs and a turnbuckle adjusted toothed packer. It works soil to a 50cm (9.75in) depth.
Stocks Flow Lift is designed to bust plough pans and loosen soil at modest depths without excessive surface disturbance. But it can also work deeper. The range now includes a medium-duty model.
THE answer, as someone famously used to say, lies in the soil. The answer, that is, to fields that remain wet too long after heavy rainfall and crops that fail to put down deep enough roots to combat drought.
In the course of their duties, tractors and field machinery of all kinds impose a weighty burden on soils. Large tyres and flexible tracks help spread the load but damage is done nonetheless to natural soil structures.
Compacted soil contains less oxygen, offers fewer easy routes for plant roots to develop and slows natural drainage of excess moisture. And, since some degree of compaction is inevitable on all but the lightest soils, subsoiling is a routine remedial operation for most growers.
The aim of subsoiling is to undo some of the damage; to recreate fissures and a more open soil profile. As such, it is best done when the soil is relatively dry. When too wet and elastic, subsoiler tines tend to pass through with little effect – ideal conditions for drawing mole drains through clay soils but not for the fissuring effect that subsoiling aims to achieve.
Nor are very dry conditions ideal; that simply makes it harder on the tractor, increasing the cost of what is already a relatively slow and expensive operation.
Two other key rules apply – first, inspect the soil profile to establish whether subsoiling is strictly needed; second, work no deeper than necessary.
It is reasonable to assume structural damage but better to confirm it by digging a profile pit. That will help determine the extent and depth of any compaction present and point to how intensive and to what depth remedial work with a subsoiler needs to be carried out.
With bigger tractors now available on-farm, subsoiler manufacturers have had to come up with more robust implements. And they dont come much more robust than the Maxi-Lift from Tim Howard Engineering.
The range starts with three- and five-leg models using a simple V-frame and extends to a nine-leg trailed design. Both implements use 200mm x 10mm square box-section for the V- or A-form frames but doubled up on the bigger implement to cope with tractors in the 450hp to 600hp league.
All versions come with a hydraulically-adjusted toothed packer roll to level off any surface heave and help with depth control. Prices climb from £3,500 for a 2.25m three-leg Maxi-Lift 250 series to £16,500 for a nine-leg 6.3m trailed 600 series implement.
More recently, a trip-leg arrangement has become available as an alternative to shear bolt protection, providing a more convenient solution on extra-heavy soils.
This is also an option on the 300 series Flatliner from Simba. Comprising a hefty compression coil spring, the mechanism allows the leg some rearward movement to clear stones and other obstructions before moving it back into the working position.
The 300 series is designed for working depths down to 30cm and comes in three- to nine-tine sizes covering four working widths from 3m to 4.2m for tractors up to 160hp. A seven-leg model is £6,474 or £10,.868 with trip-legs.
Simbas 500 series, using 150mm x 150mm x 10mm steel for the triangular shaped frame, works to 50cm and covers the same widths as the 300 series but with three, five or seven legs. Prices start at £5,946.
A toothed steel packer is standard in each case, with depth wheels, trailing kit and additional tines among the options.
The Marquis five-leg subsoiler from Browns Agricultural is designed for tractors of 140hp and more. The frame design is unusual in having a narrow leading section to carry a tine, then a full-width two-bar section carrying two tines each to form a V configuration.
The frame is constructed from 200mm x 100mm box section and a turnbuckle adjusted open cage roller – principally for depth control – completes the implement.
List price is £5,800, plus £70/leg for the optional wing kits that give extra soil lift.
Mounting subsoiler tines on pivots is an alternative to a rigid clamp, the main attraction being that steering movement is not translated into sideways stress on the tines. It is certainly worth considering when a mounted implement is to be used on a tracklayer or articulated wheel tractor.
Fosters Acre-Master range includes pivot-leg models – as well as rigid tines – on two- and three-leg subsoilers or on a 3.6m double-beam frame with up to five tines.
Broad screw-adjusted depth wheels can be added, along with a full-width open cage crumbler. Prices start at £1,350 for a twin leg model; depth wheels add £650, wings £60/leg and a crumbler £1,000.
The aptly named Loosen It subsoiler from Farmrite Fabrications carries pivot mounted tines on a single beam in swept-back formation. Largest models are five- and seven-tine implements for tractors of 200hp plus and are capable of working at depths from 200mm to 500mm.
A disc coulter can be added ahead of each tine to reduce soil deformation at the surface while a reversible bar point and wings give extra heave down below.
Buyers have a choice of open bar crumbler or toothed packer to complete the implement, adding £1,245 and £1,645 respectively to the £4,985 and £6,895 list prices of the five- and seven-leg models.
The expanded range of V-Form subsoilers from Cousins of Emneth are similar in using swept-back tool bars but feature rigid mounted tines and trailed models.
A 3.75m wide version – in both mounted and trailed format – slots into the range along with a 2.75m mounted implement. That increases the number of sizes available to five, from 2.25m to 4.25m, to cater for a wider range of tractor power and soil types.
The biggest model in each case, fitted with seven or nine legs, costs £9,120 and £10,240 with toothed packer, while the trailed variant is £12,280 and £13,400.
Heavy duty models have 200mm x 100mm box section tool bar beams with turnbuckle adjustment of the depth wheels and finishing roller and there is a three-way choice for the latter of open cage crumbler, tooth packer or steel coil.
The subsoiler design that originated the shallow soil-loosening concept is currently available in two guises – as the Flat-Life from Spaldings and the Flow-Lift from Richard Stocks.
Both implements have extended points and broad wings on forward angled pivot mounted tines to provide effective pan-busting without leaving a rough, uneven surface.
The latest addition to the Flow-Lift range is a medium duty model designed for tractors of 140hp to 290hp. The hefty frame carries up to seven tines with optional leading discs helping their passage through the soil. A three-leg model is £3,897, plus depth wheels or toothed packer or levelling coil.
Browns 01525 375157
Cousins 01945 584600
Farmrite 01751 431250
Foster 01482 868800
Richard Stocks 01945 464909
Simba 01529 304654
Spaldings 01522 500600
Tim Howard 01353 863113
NB: This does not constitute a full list of subsoiler suppliers.