USING A cover crop as a protection for products which sterilise soil to control potato cyst nematode (PCN) control can stop dangerous soil erosion.

Applying PCN treatment, then leaving it bare over the winter until the next crop goes in, is standard practice. But this can result in detrimental soil erosion as when winter conditions take their toll.

David Hildred, of Boston Crop Sprayers, was asked by a client to look into how to establish a cover crop such as mustard whilst sterilising the soil with metam-sodium (Metam) for PCN control.

“We discussed the idea of sowing mustard seed whilst applying the Metam as the soil temperature and moisture required for applying the chemical are also ideal for mustard establishment," he said.

"This is a fairly new concept, so we needed to look into the best way to get the seed drilled whilst applying the Metam. We began experimenting last autumn by walking alongside the Metam applicator and manually throwing the mustard seed between the levelling boards and the hydraulic roller as we were smearing off the soil.

“We did manage to establish a good mustard crop in this way, which was then left over the winter before being chopped and incorporated ahead of the next potato crop,” he said.

He was really pleased with the results, having seen a definite reduction in soil erosion. “However, we had to find a better way of establishing the crop alongside the Metam application.

“So we looked at fitting a Stocks micro meter applicator with two hoppers to the steriliser with 12 deflector cones, after the rotavator's levelling boards and before the roller, giving a 3.2m working width.

“So far this season, we have trialled this method over about 100ha, using brown mustard seed at a rate of 5kg/ha, and the mustard has established well.

“It’s worth remembering that in 2015 the Metam label recommendation was reduced to 300l/ha so any additional control is an advantage for PCN control and the mustard crop also offers bio fumigant activity, although this has not been properly quantified in trials,” he pointed out.