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  • Writer's picturePhilip

Ohh for a few Billion More …. Earthworms, that is!

One can hardly fail to miss the onslaught of discussion and publications extoling the virtues of “reduced cultivations” (in all there forms) and the great benefits to be had in terms of what the Sustainable Farm Initiative has in store for just about everybody (in the world.)

One of the Comics recently published a review of one such “trial” and the data from 5 years of work comparing three systems across two farms. It stated that “direct drilling had increase profitability as well as reduced greenhouse gas emissions and increase earthworm numbers.”

In the report it noted that environmental benefits have been achieved “with soil health, positive trends are starting but since these trends require more than five years to actually occur;” soil health is still pretty much as it was.

“On the heavy soil it is hoped that compaction can be managed by growing cover crops but it is acknowledged that sometimes the use of metal, low-disturbance subsoiling is required.”

Yield and Economics

“One effect of direct drilling was the lower crop establishment rate as establishment can be more challenging. On the heavy land this reduced plant population led to a yield penalty, with yield effects being greatest in spring crops. On the best soils yield was unchanged as crops were able to compensate in the more favourable soil.”

It went on to say, “with a reduction in yield margins are only improved a small amount despite 45% lower fuel use and 11% lower operation cost. On the best land benefits translated to a 9% improvement in gross margin. But it is also worth bearing in mind that gross output and yield is not everything. Taking the lower capital cost and lower tractor horsepower requirement into account there are additional financial benefits to be had. The new Sustainable Farming Incentive may encourage farmers to do more direct drilling and this might benefit them.”

To me there appears to be lots of ifs, maybe’s, might’s and buts in this published report on 5 years of funded work.

I do seem to remember something else being published in 1998 by the HGCA. The 71 page document contained the following text in its opening lines.

“During the last 15 years fixed costs on cereal farms have increased by about 40% in real terms while output from cereals has only risen by about 15%. Cereal prices are now static or falling and the scope for farmers to increase yield is small. In these circumstances the need to reduce fixed costs is urgent. The purpose of this review is to examine what is known about reduced tillage and to consider the opportunities that safer shallow tillage systems offer in reducing cost per ton of grain produced.

Long-term experiments proved that well-managed shallow cultivation and direct drilling usually gave as good or better yields of winter sown crops as ploughing,

For the clay lands straw burning and shallow tillage was successful in giving good quality seedbeds and much faster work rates, leading to uniform early establishment of crops.

However, early in the present decade, the majority of those farmers practicing reduced tillage moved back to ploughing.

There were probably three main reasons prompting this change:

1) Build-up of grass weed pressure - in particular from brome;

2) Restrictions on straw burning;

3) Compaction sustained during wet seasons and by repeated cultivation at one depth.

Although these problems were apparent to researchers, results from experiments - other than with surface straw - did not highlight their effects because in general experiments were designed to avoid them.

The insidious build-up of grass weeds in reduced tillage was at first dismissed as of minor importance but eventually it was recognised as one of the major limitations.

Climate was seen to play a major role in the success of reduced tillage. In the wetter northern arable areas of Britain only well-drained light loans were found to be suitable, in contrast to the findings in the drier south.”

The weather this season has been at best “challenging” and the yields achieved in all crop types across the UK? Hardly record breaking. One of the greatest challenges in fields where “reduced tillage” is practiced – “drainage” however you wish to define it.


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