Making no-till farming work in wet and dry conditions

Successful no-till systems are giving more consistent crop performance – especially in the most difficult years – while allowing growers to manage whatever the weather throws at them.

The resulting improvements in both soil health and organic matter content help with water management, provide more travelling opportunities and give better crop establishment.

See also: Spring crops lead battle against blackgrass

Those are just some of the findings of Nuffield scholar and Cambridgeshire farmer Russell McKenzie, who has spent the past 18 months investigating how to succeed with no-till systems, visiting leading farmers and researchers in Australia, New Zealand, the US, South America and Europe.

But having seen no-till systems being used to good effect in a variety of situations and climates, including both very wet and very dry conditions, Mr McKenzie is clear there is no prescription for the optimum system.

“Although no-till was improving the ability to farm in difficult climates, it quickly became apparent that there is no one-size-fits-all approach,” he stresses.

Starting point

“However, everyone involved had started from the same point – understanding what soil conditions they were dealing with, and then setting out to get the best from them in challenging and changing circumstances.”

Encouragingly, they were also improving soil health and structure by taking a long-term approach to the system, recording incremental improvements over a period of time and being patient when the conditions were not in their favour.

“Patience is not something farmers are known for, especially when it comes to drilling,” acknowledges Mr McKenzie. “But it is essential with no-till. It can take four to five years before farmers start to see any real benefits – instant rewards don’t always happen.”

Russell-McKenzie

Russell McKenzie

The conditions have to be right for drilling because establishment is so important to the end result, he stresses.

“If it’s wet, as it can be in the UK, you have to wait for a dry crust to form on the soil surface before drilling, especially with a disc-based drill. If you don’t, smearing and poor slot closure – leading to sub-optimal establishment – can occur.”

He points out that soil stickiness reduces as the soil organic matter content rises, which is why it is really important to have improving soil organic matter content as a long-term aim.

“Nowhere is this more important than here at home in England. We have a bias towards autumn cropping, which means soils tend to get wetter and colder as we drill. Being able to travel on them is essential.”

On many of the farms Mr McKenzie visited, cover crops were an integral part of the system. “Cover crops are fulfilling a number of roles, from helping with soil structure to capturing nutrients and improving organic matter,” he reports. “But most important is the fact there is cover, at all times.”

None of the no-till farmers he made contact with considered bare soil to be a good idea, he says.

“This is because a living cover in the absence of a crop prevents soil erosion and degradation, including slumping after heavy rainfall, while residue in-crop acts as a barrier, helping to keep soil moisture in place and regulating soil temperature.”

Although we don’t have such weather extremes to deal with, in-crop cover is important in the UK too, confirms Mr McKenzie.

“But you have to be careful with high levels of residue in spring crops on heavy soils, as the soil has to be dry enough to be workable. If the soils are active enough, it will happen as you want it to.”

The concept of crop residue as a friend will be a mental barrier for some growers, he accepts. “There’s always been a concern that it will impede crop development. You have to appreciate that the conversion of surface residue into organic matter will speed up over time.”

Wet, heavy soils

Despite what the sceptics may think, succeeding with no-till in wet conditions, even on heavy soils, is possible, he adds.

“Having spoken to farmers who have made it work, there were three things that stood out. They were all prepared to switch to spring cropping rather than drill in adverse autumn conditions, they used cover crops to prevent soil slumping and had diverse rotations.”

The root systems from these diverse rotations offered different characteristics – with some crops having roots that grew straight down, while others had more fibrous, sideways-growing roots. The combined effect of these was better water infiltration.

“Diverse rotations also helped with weed control strategies. There were more opportunities to get good control, without an over-reliance on chemicals.”

In very dry areas, Mr McKenzie came across other critical factors. These included residue retention to prevent moisture loss, inter-row or close-row planting to preserve moisture, optimum stubble height to protect against wind erosion and ensuring slot closure at drilling.

“In these conditions, it’s all about making the most of any moisture that is present.”

Russell McKenzie’s top tips for achieving no-till success

  1. Stand back – identify the most challenging drilling conditions you can face to customise cropping.
  2. Consider rotation – you need to direct drill sequential crops that balance carbon, to avoid the pitfalls of consecutive high-carbon crops.
  3. Use cover crops as a structural and water management tool, and to gain from their contribution to soil structure, organic matter and nutrient capture, rather than looking for direct returns.
  4. Pay attention – understand the effect of decaying cover crop material and the timing of cover crop destruction.
  5. Wait – in wet conditions, a dry surface crust is crucial to success, even though this may be difficult to achieve in the autumn.
  6. Weeds – understand the weed dynamics of the farm, the effect of different drills and the rotation.
  7. Establishment is everything. The windows are greater, but choosing the right day is essential.
  8. Sub-soiling – cover crops alone cannot sort out bad compaction, so consider sub-soiling for a more instant fix and achieving a long-term gain on the farm.
  9. Drill – choose the right one for your farm and situation, understand its limitations and how it can cope with weather extremes.
  10. Be patient – instant results are rare, so remember the four-stage process and that cost savings are an added bonus.
  11. Blueprint – there is no right or wrong way, no right or wrong drill; there are some machines that tick all the boxes, but individual farm requirements and budgets should prevail.
  12. Be positive – the right attitude and willingness are required to make the system work.

The full version of Russell’s article can be found on the Nuffield website.