Double OSR cropping shows promise in black-grass battle

Second objective

The second objective of the trials is to determine whether other issues arise from increased disease and insect pressure.

Comparing the double OSR crop with the neighbouring crop, Mr Ruff says: “Both crops have had near identical herbicides but what I am more interested in is whether anything is going to come back and bite us disease or pathology wise. The principal is simple enough, but this is the big question growing two OSR crops back-to-back.”

At present leaf spot and phoma levels are no different to the adjacent field says Mr Ruff.

“If anything, we are watching out for verticillium which could be an issue, but there are no visible symptoms.”

The risk of clubroot is higher with the introduction of a second OSR crop, but Mr Ruff says none has been detected, although it may be too early to tell.

“We have had reports of clubroot around the country, but from what we have pulled up there is no visible issue and it is looking very well indeed. If it is a problem we would have to pick varieties that are more tolerant.”

Neither crops have been heavily hit by cabbage stem flea beetle attack which Mr Ruff puts down to early drilling.

“It is almost conspicuous by its absence. There are a few holes in leaf petioles but certainly nothing in the main stem. It might be luck of the season – crops were established relatively early into good seedbeds and got away well.”

Growing a conventional OSR variety in the first year and a Clearfield variety in the second year means volunteers are cleared up, which Mr Ruff hopes will further reduce disease pressure.

“This theory is beautifully simple and control is looking very good,” says Mr Ruff. “It probably gives you a better return than chucking in spring barley which can crash and burn, and it can have a late flush of black-grass, so you end up back at square one.

“If it proves to be advantages, theoretically two OSR crops followed by beans, a couple of wheat crops, a barley and back into OSR could well be an option going forward.

“So far, there is no eureka moment but there are no negatives. Ultimately we will follow it to harvest and see if anything else comes through.”