In this respect many readers will have notice that in recent years there has been a trend away from ploughing land following harvest towards what is known as “minimum tillage” where the farmers pass over the stubble with a various types of machinery which usually comprise a combination of discs and tines of one form or another. The seed for the next crop is then “direct drilled” in to the seed bed which has been created. This makes sense on various levels; first it maintains the soil structure which is otherwise broken up during conventional cultivation techniques because a plough basically inverts the soil. Once ploughed the soil has to be broken down again by various other machines to create a suitable seed bed in to which the next crop can be drilled. This work is in itself expensive in terms of machinery and fuel.
At another level the minimum tillage techniques are also believed to preserve an better population of earthworms which help with the soil structure and having been on one farm walk earlier in the year, it was clear that this technique had retained far more moisture in the soil than would otherwise have been the case had the soil been ploughed. This has been particularly important in recent dry years when spring sown crops in particular have suffered from the drought conditions.
However, what I had not realised until I read a recent report of some field trials is that there can be a very significant benefit in yields for wheat crops which have been the direct drilled rather than using conventional cultivation techniques.
A recent study carried out in Suffolk has shown that the average yield from 31 plots which were direct drilled was 3.7t/acre as opposed to an average yield from all the conventionally drilled plots of 2.9t/acre. This represents an increased yield of over 25% which seems quite staggering to me and begs the question why everyone is not adopting this technique.
One reason is perhaps the fear that it is more difficult to control weeds, which is probably true, particularly for such things as “black grass” which can be very pernicious but the benefits of minimum tillage do seem quite compelling and so I suspect this will be an increasing trend for many arable farmers.
James Stephen MRICS FAAV
Rural Practice Chartered Surveyor, Wells