Agronomy shouldn’t hold back direct drill conversion

In increasing number of growers are looking at the option of direct drilling, and the perceived reasons for not moving in that direction are diminishing all the time.

Pulling steel through the soil is an expensive fixed costs on many farms, so there is no harm considering the alternatives, while the ever-increasing number of tine and disc drill designs are increasing the likelihood of finding an option that will be practical on farm.

The system won’t suit every grower, but could appeal to more than many think when you compare it with a conventional system. UK growers are well provided for with sophisticated and effective programmes, backed up by high levels of technology and support.

Indeed, as soon as someone suggests a crop type is unsuitable for a direct drilling or non-inversion system, there are those that make the point of developing a solution for the problem, so it is unlikely that any crop is outside the scope of direct drilling.

Our understanding of soils, however, still has some way to go, not least because it is difficult to conduct meaningful trials on the effects of soils and soil maintenance. Often the effects of a system can take several years to manifest themselves and then the same time to rectify, assuming we know what action to take.

The transition to a direct drilling system can take a few years, and, therefore potentially for the benefits, such as an improved soil structure and increased worm populations, to become obvious. But in the long term there can be significant benefits to the long term health of soils.

Highlighting the concerns of a direct drill system is no different from highlighting the concerns of a conventional system – they just fall in different places.

Grassweed control is often perceived to be a significant threat in a direct drill system. But if you look at the issues carefully, there are ways to mitigate the problem.

In winter wheat, with a range of relatively new contact-acting grassweed herbicides, the ability to control grassweeds is better in most situations than 10 years ago, with one major exception: blackgrass. This remains the most challenging area for growers using a direct drill system. But that is also true of most conventional systems too.

In a direct drill system, one potential advantage is that most grassweed seeds remain near the surface rather than buried to depth meaning you should know what you are dealing with.

But the key is applying some of the principles of cultural control in direct drill systems. If growers use glyphosate to kill any germinating weeds, delay drilling, preferably until October if possible, where blackgrass populations are high, and choose varieties with good competitive growth properties to drill with higher seed rates, then there is no reason why blackgrass control can’t be as good as in other systems.


In winter barley, growers should choose sites for the crop more carefully, as the cultural and pesticide options are more restricted. Late drilling of winter barley is not advisable. However, winter barley is naturally more competitive.

Direct drilled oilseed rape, as with conventional systems, offers growers a number of options to control grassweeds, so makes a natural break crop option.

The system allows growers to retain moisture in the seed-bed, which is often an issue when establishing oilseed rape in conventional cultivation systems.

Crop safety when using residual herbicides is an issue that has been raised in the past. But with new drill designs this is an improving picture, as the main issue revolves around seed depth and seed-to-soil coverage. Residual herbicides usually state a depth to which seed must be covered to ensure the herbicide does not get in contact with the seed, which is no different to conventional systems, so a bit of time spent adjusting the drill should mean this is achievable.

One other area to be careful with is the use of sulfonylurea herbicides in direct drill systems, where any residual herbicide left in the soil can effect the establishment of following crops. Again forward thinking is often all that is needed to prevent unforeseen problems developing.

Read more on direct drilling on our dedicated page.

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