The care of spring oilseed rape does not differ from that of winter oilseed rape, but in this case development takes place over a short period of time, which is limiting for yield potential, and generative plants are formed at quite high temperatures, so sowing must be timely, observations must be frequent and effective pest control must be carried out.
Soil tillage: Canola requires a fine crumbly soil bed and all efforts are directed towards this. After winter, the soils in our area are usually in optimum condition. Spring pre-sowing tillage should not be on wet soil to prevent the seedbed from becoming compacted, and should be carried out when the soil is sufficiently dry and immediately before sowing.
Sowing: Sowing should take place as early as possible in spring, at the earliest opportunity to enter the field in late February, early March. This will give the plants time for more vigorous vegetative development. Young rapeseed plants can withstand frosts down to minus 3-4 degrees, but if colder temperatures are expected, it is better to wait to sow, but not to delay after 15 March. Germination starts as early as 2-3 degrees.
The sowing rate is 80-100 germinated seeds/sq m for linear varieties and 70-80 germinated seeds/sq m for hybrids.
The sowing depth is 1-2 cm, up to a maximum of 3 cm. As the soil is wetter in early spring, no raining is necessary if the soil is well aligned and the drills have tamping wheels or levelling bodies after the boot. In exceptional conditions on very dry sites, rolling may be used.
Fertilisation: Due to the short growing season, spring rapeseed has a weaker and shallower root system and therefore requires more available nutrients. In principle, 7 kg P2O5, 16 kg K2O and 5 kg MgO per dcaa should be provided with the main fertiliser application in autumn and from soil reserves.
Nitrogen fertilization implies amounts of about 5-6 kg N/dcaa for every 100 kg yield per acre, so with a target of 250-300 kg/dcaa, 12-15 kg.acre N should be supplied.
This is done in 2 rates - 2/3 is applied pre-sowing (e.g. 8 kg N/dcaa) and 1/3 is applied as the central stem grows (approx. 4 kg N/dcaa).
Sulphur is recommended at rates of 2-3 kg/dcaa. BORON is mandatory in the initial stages of development when sufficient foliage is formed - at a dose of 30 g/dcaa. It is wrong to wait for budding to apply boron.
Weed control: All herbicides registered for oilseed rape may be used at the stages indicated by the manufacturer.
Important: Bear in mind that spring rapeseed becomes a weed background on the land for winter rapeseed that may follow in a few years' time, so after harvest a very important measure is to provoke the volunteers and kill them.
Plant protection: The main enemies here are also the flower weevil and various stem borers, as well as the pod borer. The threshold for economic damage for the canola flowerworm is 1-2 adults per plant, appearing as soon as the first buds of the plants appear. Caterpillars are monitored using yellow vessels.
Of the diseases, the most important are sclerotinia and alternaria , so a single flowering spray with a registered fungicide is recommended. A pre-flowering spray can also be applied but will have no effect on sclerotinia. Foma is not a relevant pathogen here, as the incubation period of this disease is longer than the vegetation period of spring rape.
After spring rapeseed, it is logical that a winter cereal crop should follow in the rotation, which will make best use of rapeseed as an excellent precursor.
17.02.2017
Ing. Evelina Marinova