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Soil health key to effective black-grass control - James Boswell - South East Farmer

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Improving soil health is fundamental to good black-grass control and the coming weeks are a crucial time to shape success in the coming season is the advice from Kent based agronomist James Boswell.

The 2017/18 season has been another tricky one for black-grass control leaving some growers questioning where to go next.

However, it’s key to remember that careful soil management and improving soil health are the most important factors in black-grass control. The best way to reduce populations is to keep weed seeds in the top 50mm where they can be managed-out in a controlled way, allowing deeper seeds to degrade naturally.

The dry conditions this harvest provide the ideal opportunity to transition to a shallow tillage system on those fields worst-affected by black-grass. It’s about protecting and enhancing the natural structure with biological rather than physical management.

Deep cultivations such as subsoiling or ploughing should be avoided unless absolutely necessary, as this risks bringing up old seed from depth and burying freshly-shed seed for future years. It also damages natural structuring, earthworm populations and buries organic matter deeper in the profile.

It’s also important to avoid over cultivating the surface layer in shallow tillage systems, he adds.

The top 50mm is the most friable part of the soil. If it’s too fine it will be unstable and harder to drill if conditions are wet in October.

Do remember that patience is key to effective black-grass control and no more so than this autumn. As Hutchinsons warned last month stale seedbeds will be ineffective where soils are very dry, and growers must wait for adequate soil moisture to achieve a good flush of black-grass before drilling.

Most black-grass emerges between mid-September to mid-October, so at-risk fields should not be drilled until after this time, otherwise there is likely to be a flush of black-grass within the crop that is extremely hard to control with limited post-emergence chemistry.