26th October 2015
Oil radish approval offers great greening opportunity for growers
Scottish growers will soon be able to include oil radish in their EFAs after changes to greening requirements have placed the crop on the list of approved crops from 2016. As a versatile crop with numerous benefits, authorisation from the Scottish government to include oil radish is fantastic news for growers.
Oil radish is a quick growing brassica crop and excellent at catching residual nitrogen; Kings and Frontier research has consistently shown N capture of up to 150kg/ha. This allows valuable nitrogen to be recycled into the following crop as well as reducing leaching. This nitrogen is caught by a robust taproot and lateral fibrous roots which can reach down to over 18 inches, busting through moderate levels of compaction as they grow. It has a high level of clubroot resistance too, so won’t affect brassicas in a rotation.
Grower Stephen Melville hosts Kings’ cover crop trials in Fife and highly recommends oil radish. “It has great ability to soak up nitrogen from within the soil and make it available for future crops. This helps to reduce manufactured fertiliser requirements, so it’s beneficial for the environment and my pocket. Oil radish is also a good feed source for livestock, helping to provide valuable winter forage. Crucially, it’s a very quick germinating crop, unlike some of the other EFA options, which is especially useful given the slightly later establishment dates and the risk of deteriorating climatic and soil conditions that we can face in Scotland.”
Soil structure can also be greatly improved with oil radish. Trials have shown that it has the potential to produce huge quantities of biomass, with up to 30t/ha of fresh matter. Around 10% of this is dry matter which contributes to soil organic matter levels, revitalising the soil, improving soil structure and increasing valuable humus content.
New to the world of cover crops this year, David Jenkinson has grown oil radish for the first time in a bid to improve soil structure at his farm in East Lothian. “I’ve been very impressed with the crop, especially considering it was late going in as it established very quickly. I’m become an avid believer in cover crops and think that there’s a huge place for cultivation with plants rather than steel. I chose oil radish for its benefits to soil structure and I haven’t been disappointed.”
Trials have been key to oil radish being added to the approved EFA crop lists in England, as announced in September, and now in Scotland. Recognising the crop’s significant benefits for arable rotations, Kings actively campaigned for the inclusion of oil radish for over a year. This included trialling the crop at several of its demonstration sites, including Coldstream, Haddington and St Andrews in 2014 and an extended network covering sites from Coldstream to the Black Isle in 2015. Kings is also working with the James Hutton Institute in Scotland to gain a greater understanding of how various crops interact with a range of soil properties.
Manager Richard Barnes is delighted at the recent announcement, “Kings has long extolled the virtues of oil radish. It’s such a versatile crop that we have been encouraging and supporting growers to sow it even outside of EFA rules, so it’s fantastic news that it can now count as one of the crops under greening requirements.”
Greening rules in Scotland state that growers incorporating Ecological Focus Areas (EFAs) into their Scottish Rural Development Programme must: - establish the EFA green cover between 1 March and 1 October inclusive - maintain the EFA green cover up to the 31 December inclusive - incorporate the EFA green cover as a soil conditioner before establishment of the following years’ harvestable crop - establish a green cover consisting of two or more of only the following crops: alfalfa, barley, clover, mustard, oats, phacelia, oil radish, rye, triticale, vetch.
A vetch and radish mix is generally recommended for early sowing in August, Richard explains, or a rye, oats and radish mix if sowing in September. For advice on the best approach according to individual circumstances, talk to the experts.