Programmed fungicide use and variety choice leads to higher rape yields
Choosing hybrid oilseed rape varieties and managing them well with attention to detail throughout has substantially improved the yields of oilseed rape on a North Yorkshire estate.
"West Heslerton Farms near Malton in North Yorkshire comprises of 370 arable hectares on thin chalk soils along the northern edge of the Wolds to very light sandy soils in the Vale of Pickering. The farm has grown winter oilseed rape for many years but yields were restricted by the depth of soil, often only 6 inches over chalk bed-rock. Yields have improved as a consequence of a number of management decisions including the use of hybrid varieties which over-winter better on these higher exposed sites; through improved weed control using pre-emergence herbicides such as Katamaran (metazachlor and quinmerac) and for Poppies and Cleavers, the use of autumn nitrogen which helps to provide crop cover helping to prevent pigeon damage and the judicious use of fungicides in the autumn and spring. Through the implementation of these changes, yields have risen from 3 t/ha to 4.4 t/ha," says Dave Clark of May and Dawson who advises on the farm.
"When the York sugar beet factory closed and sugar beet growing in the area was badly affected, the farm needed to replace its beet crop on the sands. Peas were considered but with only moderate yields and prices, this did not appear to give a good enough return. It was decided to try out winter oilseed rape and to plant the high yielding, high vigour, restored hybrid variety Excalibur which is suitable for direct combining with glyphosate and to manage every aspect of the crop really well," explains Dave.
Dave outlines that Autumn management started with a seed rate of 60 seeds/square metre. Pre-emergence Katamaran with clomazone gave total control of broad-leaved weeds. A low dose of quizalofop–P-ethyl for volunteer cereals followed by a low dose of propyzamide for wild-oats has made the crop virtually weed-free. Autumn nitrogen was also applied to boost crop cover. A half dose of Caramba (metconazole) at 0.6 l/ha was applied in the autumn for Phoma control combined with a trace element mix containing manganese, magnesium, molybdenum and boron."
In early March the crop was walked to assess the Green Area Index and at around a GAI of 1.0, the first dressing on nitrogen and sulphur was applied with the nitrogen balance following at around green bud stage. At stem extension an application of Caramba was applied purely for growth regulation, as the autumn fungicide application had cleared up Phoma and Light Leaf Spot completely. The spring-applied Caramba was mixed with foliar phosphate and a trace element mix for known deficiencies.
The farm has had problems of pollen beetle and seed weevil in the past. The pyrethroid insecticide Contest (alpha-cypermethrin) is used when thresholds are reached.
At mid-flower the crop will receive an application of Filan (boscalid) at 0.5 kg/ha, as Dave considers that this product consistently gives improvements in yield, irrespective of whether diseases such as Sclerotinia are there at the time.
"Hopefully by manipulating the canopy effectively, the crop will be such that direct combining with glyphosate will give optimum yields and oil quality. By attention to detail to all aspects of crop management and by using the right products at the right time, we hope to produce a high yielding crop with a good return," concludes Mr. Clark.
