In the UK, average oilseed rape yields have not shown much of an increase since the early 1980s, even after accounting for the very high yields achieved in 2011, which many are tipping as the best year for oilseed rape yields so far.
Poor weather is often cited as being the main reason behind the fall in yield, with a lack of sunshine, too much rain and late frosts in the spring hampering prospects.
In terms of horticulture, the components that affect the oilseed rape yield are:
Number of plants per unit area
Number of pods per plant
Number of seeds per pod
Individual seed weight
To achieve the maximum yield potential of this year’s crop, a proper horticultural and crop management regime is needed, which should include a full nutrition programme as well as pesticide control.
One analysis of UK crops showed that in order to achieve a yield of 5 t/ha, oilseed rape must produce at least 100,000 seeds/m2. However, producing excessive pod numbers of more than 10,000 pods/m2 will not maximise the number of seeds/m2 because these crops tend to produce very thick flowering canopies, which will block more than half of the incoming light.
Plant nutrients are essential for all crops, however compared to other arable crops for eg. cereals, oilseed rape has a significant demand for nutrients in order to grow. Most of the nutrients absorbed by the oilseed rape crops tend to be returned to the soil making it an excellent preceding crop in a rotation, hence it’s popularity in the agriculture industry.
Studies have shown than application of a mineral fertiliser usually returns 4 to 5 times the money invested in crop yield. The soil can be analysed to show what it is lacking, but most farms with a poor yield tend to be lacking a key soil nutrient which is preventing it from reaching its yield potential. As any horticultural expert knows, the pH of the soil is also an important factor in rapeseed oil yield, and samples should be taken regularly to determine what is required.
Where the soil is not lacking key nutrients but the yields are still not reaching potential, check for poor drainage and soil compaction, as this can restrict rooting and therefore reduces the nutrient and water uptake.
Disease development can really affect your overall yield of rapeseed oil, especially when the conditions are regularly moist and warm. So keep a vigilant eye on your crop and take action as soon as a potential problem has been spotted, as disease can be carried over from previous crops.
Once the crop has been yielded, the storage of the crop in silos is extremely important so that little wastage occurs. Agricultural silos need to be cleaned regularly, and professional silo cleaning is often the best solution for farmers to reduced blockage and clogging.