The poor establishment and condition of oilseed crops drilled this autumn has left many growers considering what their best options will be to rectify the situation, come the spring.
Patrick Stephenson, AICC agronomist in north Yorkshire, suggests that where oilseed rape crops have been decimated by slugs, are waterlogged and poorly established, or have not even been drilled as in many northern regions, gives growers two options come the spring.
âWhere fields have not been drilled there is the choice of either leaving it fallow or considering a spring rape crop basically. Where plant populations are low, itâs a case of sitting tight and looking at how they come through the winter; rape crops often have a funny habit of still producing good yields when least expected. There is also the option of re-drilling bad patches or blocks with a spring crop.â
âItâs always hard to leave a field fallow as then itâs not making any money, the flip side of this is putting in a spring rape crop, but then you run the risk of unpredictable conditions. However, there are decent enough margins to be made from spring rape if you can get the yields up around the 2.25-2.5t/ha mark.â
âBear in mind that seed beds will still be cold coming into the spring so donât be tempted to go too soon. It is really important to get the variety right and by this I mean that with unpredictable spring conditions it will need to be one that establishes quickly and gets away. It should also have a relatively short growing period and good standing power so it doesnât fall over â some of the more popular vigorous hybrids are well suited to this slot.â
Importance of good agronomics David Waite, of Frontier, agrees and has found consistent and good yielding performance from the spring rape Delight. âDelight with its hybrid vigour, is always going to be more reliable when sowing into difficult spring conditions, than a conventional variety. We have found the variety to offer a good combination of yield and also early maturity (6) â important for growers in the north. In fact, we often see commercial crops appear earlier than the official scores would suggest. Delight has performed well with growers over the last couple of seasons and fits in well, particularly with those in the north where the pressure to get crops off in good time is high.â
Agents for Delight in the UK, Limagrain, advise that the excellent early vigour of the variety provides some flexibility in sowing date, but recommend that it should be drilled in the first three weeks of April into a fine, firm seedbed.
Lower input costs âAn advantage of putting in a spring oilseed rape crop that should not be overlooked is that generally it is a lower input crop,â says Michael Fletcher of Limagrain. âA vigorous hybrid like Delight will be able to compete with weeds and pests, whereas slower growing crops can be more difficult to manage.â
âWhere weed pressure is high however, we suggest metazachlor-based herbicide programmes are used, with clomazone added where cleavers are an issue. Disease is generally not a problem either, but where spring crops are being grown next to winter rape there can be cross infection, and where conditions are favourable Sclerotinia or Alternaria will need to be controlled with a fungicide application during flowering.â
âTwo insect pests – flea and pollen beetle- frequently cause damage to spring oilseed rape. Insecticide seed treatments will delay flea beetle attack but a follow up spray may be necessary. Pollen beetle will need to be monitored at the green to yellow bud stage and an approved insecticide applied once the threshold is reached. The thresholds have recently been reviewed and a new approach proposed which takes into account plant populations rather than just relying on the number of beetles/plant for all crops.â
Mr Fletcher adds: âItâs also worth noting that spring rape typically requires about half the amount of nitrogen of winter crops, and less P and K. Spring rape responds well to sulphur, but can be prone to boron deficiency on lighter soils so soil or tissue analysis is always important.â