East: Monitor oilseed rape for slug activity
With harvest progressing well, and the new season rapidly approaching, now is a good time to look at the state of the soil in terms of nutrient content, pH and structure. Soil testing may be time consuming, but the rewards of getting the pH and nutrient status correct are immense. With the high price of potash and phosphate it is important to target applications against crop need.
The increasing cost of diesel is an incentive to check the soil structure, sub-soiling needs to be targeted to the fields that have soil structure problems, and the depth at which the legs are pulled needs careful consideration. Digging a soil pit is the only way to determine how deep the soil needs cultivating.
Where blackgrass is a problem, the cultivations used need to be based around a blackgrass control strategy. With little seed returned to the soil this year there is a need to avoid bringing previous seasons seeds to the surface. Stale seed-beds provide a cost-effective method of reducing blackgrass populations.
We now have some early planted winter oilseed rape emerging. Drilled rape with sufficient soil coverage on high broadleaved weed pressure fields will be receiving a split dose of a matazachlor-based product. The first of these applications will be made within 48 hours of drilling and the second soon after fully expanded cotyledons. Quinmerac will be the preferred partner in poppy situations, and dimethenamid-p in cranesbill situations.
Crops established by sub-soiling will be treated for broadleaved weeds at the expanded cotyledon stage. We must also bear in mind the metazachlor limit, which is up to 1000g/ha of active ingredient applied one year in three.
Monitoring for slug activity is a priority in rape crops, particularly those established by sub-soiling. Early intervention is essential because damage to young plants will reduce plant populations and potentially crop yield. Best practice advice is to not exceed a maximum total dose of metaldehyde of 160g/ha between 1 August and 31 December, and 1.5% pellets can help achieve this goal.
Due to concerns over metaldehyde getting into watercourses we should try to use alternative effective products, such as ferric phoshate, which I’m recommending on headlands near watercourses. It is important to remember that metaldehyde has a six-metre no spread zone near a watercourse.
