A growing choice
Direct drills are firmly back in vogue as the emphasis shifts towards boosting soil health as well as cutting establishment costs. Some machines will only perform to their best in no-till conditions – working into the firm surface underneath stubble, or fresh or sprayed-off residues, and these are suited to farms or parts of the farm already well down the ‘no-till journey’. But on some soils, certain fields or even the whole farm may not be possible to direct drill every year, even when the cropping regime and programme has been geared towards it. Drills that can be adjusted or adapted to work in min-till and even cultivated seedbeds offer flexibility in this situation, or where the system is being transitioned to direct drilling. Modern direct drills are more versatile in other ways too – there are now plenty of options to place fertiliser at drilling to give crops a good start, whether liquid or granular, while split or supplementary tanks allow companion crops, multiple cover crop types or slug pellets to be put down the spout.
The old dilemma persists – disc or tine? Exponents of tines claim that they create more of a tilth for the seed and that they are more versatile, with contour following making it easier to work into cultivated or min-till seedbeds if necessary. Hard-faced tines can help to keep costs down compared to replacing discs and bearings. Downforce is provided by the inherent design of a chisel opener, reducing the weight needed to penetrate the surface.
Disc drills can offer reliable ground penetration in hard conditions, aided by angling of the opener disc, and can cut through residues and even standing cover crops. The reduced soil disturbance is of use where grass weeds are an issue, avoiding the risk of pulling weed seeds up from below and encouraging then to germinate in the row. The weight of the unit and down-pressure to the discs helps maintain even seeding depth at higher forward speeds, on dry soils and unlevel terrain.
The proof of the pudding as they say is in the eating, and with
