Workshop: Under sowing grass into standing maize with homemade drill

“The seeder came off an old rape drill that was no longer used. Along with the new coulters, we used new pipework and fittings throughout. A bit of hot water and the 50mm pipe easily slipped into the coulter units,” he adds.

Rate control is governed with a GPS speed sensor on top of the tractor cab. Tractor of choice for this task is a Ford 5610, says Mr Mackintosh. Fitted with an original set of tyres, the same width as modern row crops, he says the old tractor has just enough lifting capacity to hoist the drill out of the ground and pulls it well, right up to its seventh gear when it runs out of steam. However, the tractor itself does not have GPS steering, requiring the operator to manually steer down the rows, which is an easy enough task, given the maize is planted with GPS, says Mr Mackintosh.

Grass is sown at 8kg/ha with work rates of up to 40ha per day achievable, reports Mr Mackintosh. “We tend to let the maize get away, then when it is around knee height at the six to eight leaf stage, we will sow the grass. This is a good time as the plants are well established and still short enough to get under the seeding bar. The seed needs to go into moisture and loose soil. The press wheel on the back of the coulter does enough consolidation so that the seed sits in a seam of moisture,” says Mr Mackintosh.

However, the whole of the farm’s maize area is not under sown with grass. Instead, a policy of targeting the farm’s problem fields is implemented, with the aim of improving the soil structure and ability to travel. He says this year 200ha was undersown. This included fields that suffer from flooding and lie wet at harvest, he says.

“There is a noticeable difference when driving on the fields that have been undersown, with trailer tyres staying cleaner and making less of a depression, thanks to the mat of roots from the grass plants. The ground feels firmer and there is definitely less movement in the soil. We have not had any major mishaps with trailers getting stuck this year, so it certainly makes a difference to the weight the ground can carry.

“The grass also stops water sheeting off the fields in periods of heavy rainfall and acts like a filter for soil as water travels to the ditches,” adds Mr Mackintosh.

Once the maize has been harvested, the grass is left over winter, with some fields grazed by sheep. “The grass is incorporated ahead of planting, providing valuable nutrients to the growing maize plants the following year,” he says.

In addition, the farm direct drills wholecrop mixes into the grass and maize stubble and this year has experimented with rolling the growing grass plants after the maize has been removed. The idea behind the process is it gives the grass a growth kick, as well as flattening and snapping off more of the maize stalks, which should encourage them to rot down quicker and be less of an issue when harvesting the wholecrop.

Overall, the homemade interrow drill is a valuable addition to Mackintosh Maize’s fleet and is proving to be a cost effective tool for improving the land farmed, with nutritional, environmental and logistical benefits, says Mr Mackintosh.