West: Take care with seed calculations

Here is my first crop Crop Watch blog of the new season, however, the only crop out there to watch is winter oilseed rape – apart from a few surviving patches of last years cereals and spring beans.

Last December we installed solar panels on our roof and since then I have become an avid sunshine follower! The piece of data from my records that puts the 2012 growing season into perspective is that we had more sunshine in February and March than June and July. No sun, no photosynthesis, no photosynthesis, no yield.

Despite the crop being sown rather later than usual following the delayed harvest, rape has established well in surprisingly good seed beds. Earliest crops behind winter barley are at two to three leaves, while those following wheat are at cotyledon to first true leaf.

Blackgrass is emerging rapidly in rape seedbeds. Current favourable growing conditions will go a long way towards breaking the environmental dormancy forced on the plant by the cool wet summer.

Slug problems have not been as severe as anticipated after the huge numbers of slugs visible in cereal crops all summer. I suspect that the drier spell of weather has been better for the slugs’ natural predators and worse for the slugs resulting in a balancing of populations. This does not mean there is reason for complacency as the season progresses and wheat drilling starts.

The planned acreage of winter rape has been drilled. Swapping around of fields due to soil damage at harvest and straw clearance means that on some fields rotations have become closer than optimal.

This season has seen more straw chopped than I have ever known to allow speedier rape establishment. Growers have not been prepared to take the risk of soil damage from the tractor loaders and narrow wheeled trailers often used by livestock farmers purchasing straw, despite the not inconsiderable value of straw.

Soil sampling over the past few weeks shows lighter land in reasonable order following the summers deluge, but heavier soil types are still plastic below the surface. Definitely a year for mole drainage not soil loosening.

A further complication of the wet summer is the effect on cereal seed quality. Testing of home saved samples has, in some instances, shown germination of below 70%, this seed is likely to have reduced vigour and should not be planted. Increasing the seed rate to compensate for the reduced germination will not counter the vigour problem. Poor seed is not going to tolerate being drilled deep enough to escape slugs, then having a hefty cocktail of pre-emergence herbicides banged on top of it!

If you suddenly find yourself needing more seed do not delay in ordering, as supply is tight and many major varieties are now sold out. Thousand seed weights are low this season, so pay special attention to seed weight calculations. For the first time in many years I have seen bought in wheat seed below 40g/1000grains. When performing your calculations pay special attention to germination and seed bed losses as they bound to have a greater effect this season.  Do not be tempted to drill home saved seed without treatment – the risk of total failure due to fusarium is too high.

Good luck with the new growing season. With luck we may have a normal year, although I am starting to wonder, after the 2011 drought and 2012 deluge, if there is such a thing.

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