EVERYTHING YOU NEED TO KNOW ABOUT DIRECT DRILLING

In the beginning...

Around nine thousand years ago in the Fertile Crescent, located in today’s Middle East, the first settled farmers used sticks to scratch furrows into the soil to plant seeds, and we have been using the plough in one form or another ever since, so it comes as no surprise that after such a long-time resistance to changing farming systems without the plough are deep-seated.

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(The Fertile Crescent was a crescent-shaped region spanning modern-day Iraq, Israel, Palestinian Territories, Syria, Lebanon, Egypt, Jordan, parts of Turkey, and Iran.)

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Terminology

There is perhaps, some confusion over the terminology that has evolved around different cultivations systems, and as with all definitions there will be some exceptions, but for clarity, this article will use the following definitions.

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• Conventional cultivation - Uses a plough to invert the soil and bury the previous crop residues, followed by one or more cultivations to break the soil structure down further, before planting seed.

• Minimal cultivation - No plough is used but the soil is cultivated one or more times before planting seed.

• Direct drilling - No plough or cultivation is used before planting the seed directly into the stubble of the previous crop.

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Conventional cultivation

The purpose of conventional cultivation was to bury weeds and crop residues, to create a clean seedbed, and to maximise the contact between seed and soil which would encourage the seed to rapidly absorb moisture and germinate quickly.

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Conventional cultivation systems are very intensive in terms of the financial cost, the machinery required, and time.

Minimum cultivation

The term, minimum cultivation, does not refer to a specific cultivation system as such, but generally means a system that doesn’t use a plough and with fewer operations than conventional cultivations.

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Minimally cultivated seedbeds, if well prepared, can lead to good crop establishment and high yields at a reduced cost.

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Direct drilling

Direct drilling or no-till farming is when the crop is planted directly into the previous crop's stubble with minimum soil disturbance. 

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Reducing the number of operations required for seedbed preparation to a minimum or zero, reduces costs, conserves soil moisture, increases the amount of crop residue on the soil surface which protects the soil, and can improve the overall timeliness of farm operations.

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There are several types of specialist planters commercially available for either minimum cultivation systems or direct drilling, using discs or cultivator tines for creating openings into the soil. 

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What’s wrong with ploughing?

Although ploughing is a tried and tested method that works well in most conditions and provides a straw-free loosened soil in one pass, there are disadvantages.

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Ploughing is slow and expensive, it breaks down soil structure, damages soil flora and fauna, increases soil erosion and can lead to plough pans (a compacted layer below ploughing depth).

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The idea of lifting and inverting soil came about in order to create a clean seedbed.

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The development of direct drilling

Direct drilling and minimal cultivation have been developing in most agricultural regions, but Australia and Canada have led the way as they looked to remain competitive growing crops in dry regions.  

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Australian and Canadian farmers recognised that, in order to compete in a global market, they had to reduce their cost of production.

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As fuel was a big expense, that seemed a logical place to start.

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This encouraged farmers to look at ways of reducing the number of passes their tractors made while growing a crop, and ultimately led to direct drilling.

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Direct drilling has a mixed reputation amongst farmers as many who have tried it said it didn’t work for them.

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However, they often only tried it for one or two seasons, and although they stopped ploughing, elsewhere they managed the crop in much the same way as they had done previously.

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Talk to an Australian or Canadian farmer who operates a direct drilled system and they will tell you that there is more management involved than just not ploughing.

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The benefits of direct drilling

The main benefit is profitability; done correctly and direct drilled crops will yield just as well as a conventionally established crop, but at a significantly lower cost of production.

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Many studies have found that direct drilled farming systems can be more profitable as it reduces labour, fuel, irrigation, machinery running costs and repairs.

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It’s often perceived that direct drilling leads to lower yields but done correctly this isn’t necessarily the case.

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Direct drilling leads to better soil structure which improves water infiltration rates, more organic matter in the soil means more of that water is retained, and yields may increase as a result.

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Also yields tend to become more stable, particularly in dry years when they would normally fall.

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The higher water content also means that instead of leaving a field fallow to allow soil moisture to replenish, it is possible to plant a crop instead.

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In a direct drilled system crop residue is left on the surface, protecting the soil from water and wind erosion.

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Other benefits include better soil quality, an increase in soil biomass including bacteria and fungi, improved weed control and better soil ‘trafficability’ for machinery.

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Environmental benefits of direct drilling

There is some debate as to how much carbon is sequestered under a direct drill system, but a case can still be made for the reduction in fossil fuel, less erosion and better soil quality.

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As sustainable agriculture becomes more central to government policy, financial support will likely be increasingly linked to conservation farming methods such as direct drilling.

Resistance to adopting direct drilling

There is a great deal of resistance to changing farming systems and understandably so, there’s a lot at stake if it was to go wrong.

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But with direct drilling there is increasingly more evidence to the benefits and an improvement in our understanding of how it can be achieved successfully.

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It’s been said by farmers who have converted that it’s as much about a change in mindset or attitude as it is what type of drill is used.

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One key point to keep in mind is that direct drilled crops look different, particularly in the early stages when they look scruffy compared to conventionally established, uniform, clean rows.

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But if done correctly, when the combine goes through, you’d be hard-pressed to tell the difference.

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Green Square Agro Consulting