With increasing legislation in terms of chemicals permitted to control soilborne pests, any cultural options that can help improve yields and reduce pest and disease levels ins always advantageous. Over the last 18 months research has been going on into the use of cover crops and their biofumigation properties to control nematodes and pathogens found in soil.
How does it work?
The most commonly used biofumigants are members of the Brassica family, and in particular mustard species. These species contain glucosinalates (the compound which also makes mustard hot) that can be deadly to weeds, soilborne pathogens and nematodes.
When these species are cultivated and broken down, plant cells are broken and the glucosinalates are released. This release (combined with another enzyme) releases various other substances one of which is termed ITC's (isothiocynates). These ITC's then produce a fumigant which is similar to metam sodium.
As well as these beneficial biofumigant characteristics, the process of macerating the plants and incorporating them into the soil leads to increased soil organic matter levels and healthier, more productive soil.
One area which is the subject of research at the moment is the use of cover crops (and biofumigation) for the control of potato cyst nematode (a highly damaging parasite of potatoes). This project which is being run by SRUC and Baworth Agriculture and funded by the Potato Council is looking at how best to
incorporated these biofumigant plants into current rotations and how to grow them in the field conditions. This will allow them to develop sustainable guidance for potato growing on how to optimise their use.
The project look at the factors which may influence the efficacy of biofumigation including soil moisture / irrigation inputs and equipment used to macerate the foliage.
The project is still underway but FCCT will keep you up to date on the results. In the mean time,
Farmers Weekly have highlighted one farmer’s experiences of using cover cropping to help control PCN in his potato crop. The farmer is using a mix of caliente mustard and fodder radish which is broadcast in July after winter barley and rolled. Read more of this case study here.