Growers struggling to get oilseed rape drilled because of the late harvest are being reassured that rape yields are unlikely to suffer when planting the crop in late September.

This is according to ProCam’s 4Cast data stretching back to 2008 which shows little advantage in terms of yield of early drilling.

While best practice still points towards end of August/early September drilling, there was no major yield advantage to early or even mid August plantings, says ProCam agronomy manager Nick Myers. Interestingly, there was only 0.2 t/ha between sowings in the last week in August to the last week in September, the study showed.

“2011 was the only year to buck the trend and this was due to the early onset of winter in 2010, when later drilled crops had little time to develop adequate rooting or crop size and were unable to cope with the spring drought. Even here it was only the very late plantings where yield suffered.

Whatever the drilling date the ProCam approach hinges around crops getting off to a good start and able to establish a strong rooting system.

“This year could be the year to focus on the early establishment phase of OSR. Consider using the seed-bed fertiliser Umostart Super Zn, which is applied at drilling close to the seed,” says Mr Myers.

The firm claims that it is shown to encourage root growth, increasing root length and weight, increasing root hair numbers and maximising rapid crop establishment. In trials with eight different OSR varieties Umostart increased leaf weight by 35% and root weight by 40%.

A robust pre-emergence or early post-emergence metazachlor-based herbicide should be considered as part of the weed control programme in order to remove weed competition effectively.

Growers should be aware of new guidelines regarding metazachlor-based herbicides indicating that no more than 1,000g metazachlor a hectare can be applied over a three-year period in the same field.

Later-planted crops will need monitoring for slug activity and be prepared to treat just after drilling if necessary. Metaldehyde Stewardship Guidelines must be adhered to keep metaldehyde out of water. A maximum 700g/ha of metaldehyde a year is permitted; however, no more than 210g/ha should be applied between the 1 August and 31 December.

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