Improving soil health: Maize undersowing to improve soils

The concept of undersowing maize with grass is gaining traction, providing a field cover option post-harvest to avoid bare stubbles over winter.

Improved soil structure, more options for slurry and digestate utilisation, as well as a way to reduce soil erosion and nutrient leaching are among the benefits it can bring, says Agrovista’s technical manager Antony Wade.

Putting the concept under scrutiny, he has been involved in some of Agrovista’s maize undersowing trials which have covered establishment techniques and timings, row spacing and the importance of suitable grass mixtures to achieving the desired outcomes.

He says: “Maize is often seen as a high risk crop as it has the potential to receive high-levels of nutrients coupled with the exposed soil we see for a prolonged period, so the potential for soil run-off is high, especially in heavy rainfall or flooding."

“It is likely that maize cropping will face increasing levels of legislative scrutiny, which could mean farmers in some areas may not be allowed to leave bare stubbles over winter in the not too distant future.

“We are also increasingly moving into territory where nutrient application is becoming increasingly regulated, so getting soil into better health is crucial to making sure more of the necessary nutrients able to be released from the soil.”

Undersown grass in maize can be established in two ways, either once the maize crop is at the four to six leaf stage or into the maize seed bed as a companion crop.

Agrovista has carried out trial work on the latter, as an alternative to the more commonly practised later establishment method.

“Because maize grows quickly once it is in the ground, there is a danger that the opportunity to undersow grass at the correct growth stage can be missed using the later method and is why we are exploring dual sowing as an alternative.

“A service was set up to trial this last season in Cheshire, which sees a specially adapted drill put the grass seed in at the same time as the maize.”