Minimum tillage (min till) continues to carry all before it as the cultivation technique of choice for go ahead British arable farmers. So fashionable now is it that even the likes of DEFRA secretary of state Michael Gove proposes to encourage more UK farmers to adopt the practice with a special subsidy because he believes it improves soil structure. But is min till really something that we should all be so positive about?
The main problem with min till, of course, is that it weds the arable farmer so heavily to the use of agrochemicals. Before a new sown min till crop has emerged, glyphosate has to be used to kill any crop volunteers or any weeds that have already germinated. A barrage of other herbicides then have to be used to control the weed seeds that sit on or close to the surface of the soil that geminate along with the crop. Such endless heavy reliance on agrochemical control of weeds in turn leads to weeds developing herbicide resistance.
The plough, of course, is remarkably effective at burying many of these problems, including any dormant weed seeds that have dropped to the surface of the soil during the growing of the previous crop. Once inverted by the plough, by the time these seeds are brought to the surface again by further ploughing, many of them will no longer be viable or fertile.
And it’s not even as though min till lives up to its name. Immediately after harvest, tractors and cultivators have to dash about in a desperate attempt to encourage crop volunteers or weed seeds to germinate (which in a very dry late summer and autumn can amount to little more than a significant and costly waste of horsepower, manpower, cultivator tines, scalloped discs and diesel).
There are claims made for min till that it improves soil structure and, in many instances, I am sure that it does. But, equally, on soils that tend to compact over time, ploughing can also have a beneficial effect.
The truth of the rapid adoption of min till techniques is that, rather than being an entirely positive development, it is, instead, a reaction by farmers to the relentless long term decline in the profit to be made from growing combinable crops. Long gone are the days when a farmer could earn a good living off 250 acres of arable land (i.e. the 1970s). Now farms need to be at least double that acreage which has in turn produced a problem: how does a farmer get a plough over ever increasing acreages in the time available between harvest and the drilling date of the next crop (which, in modern arable rotations, is invariably in the autumn).
No doubt min till is here to stay, particularly if Mr Gove is going to subsidise it. But if grain prices were to rise significantly in the future it wouldn’t surprise me to see the plough make a comeback. And if glyphosate were ever banned (which remains a distinct possibility), a very significant comeback.
