20 September 1996

Subsoiling may be next to benefit from satellite guidance

New ideas in cultivation and drilling were much in evidence at last weeks Norfolk Farm Machinery Club event on an easy-going site at Barton Bendish near Kings Lynn. Peter Hill reports

SUBSOILING could be the next operation to come under satellite guidance if Simba pursues its idea of coupling a field map-reading controller to its latest disc cultivator, the Tandem Mono.

The tandem – or X- formation – disc cultivator carries a set of five conventional subsoiler tines between the two gangs and, if fitted with a hydraulic lift/lower system, could selectively subsoil under automatic control, suggests Guy Leversha of Simba. "Why waste energy subsoiling the whole field if only areas within the field need this treatment?" he questions.

Selective subsoiling is one of the first responses to yield mapping data when it identifies and quantifies the effects of localised soil compaction on crop performance, says Mr Leversha. With a GPS-guided control system and subsoiling map on board, it would be simple for the cultivator to drop the tines in where needed – even at variable depth if appropriate.

Combining the two operations, subsoiling and discing, is a logical approach, says Simba.

"If farmers have enough power to subsoil, they usually have enough to disc at the same time," notes Guy Leversha. "Apart from the savings made by doing two jobs in one go, the subsoiler tines run through partially loosened soil and there is one less pass in the cultivations programme over subsoiled ground."

The Tandem Mono is also unusual in having different disc sizes front and rear, heralding a new range of Simba offset disc cultivators with this configuration.

"In wet conditions, particularly, the rear gangs cause extra drag and tend to gum up first because they are working in loosened soil and stubble," he notes. "By fitting larger diameter discs at wider spacings for the rear gang, we gain more clearance beneath the axle for this material to pass through."

The bigger rear discs work deeper, so get extra purchase on firm soil, which reduces the tendency for offset-type implements to crab. The progressive working depth is also reckoned to cut the size of clods brought up by the discs.

There are two sizes of Tandem Mono, 3m (9ft 10in) at £19,900 and 3.7m (12ft 2in) at £21,800. Both have 70cm (28in) diameter discs spaced at 25cm (10in) on the front gang, with 80cm (32in) discs at 30cm (12in) on the rear. These correspond with the gangs used on Simba 2B and 3B disc cultivators, respectively.

The same format will be available for 3m, 4.26m and 5.5m (9ft 10in, 14ft and 18ft) offset – or V-formation – implements, as well as a combination of 3B-spec front gang plus 4B rear gang – 91cm (36in) discs at 41cm (16in) spacing – in 3.65m and 4.8m (12ft and 16ft) sizes.

Subsoiling under satellite guidance is on the cards with Simbas latest disc/subsoiler combination, the five-leg, two-gang Tandem Mono.