February 16, 2015
South: A decent spell of winter but not enough yet
Well, December and January have actually given us some winter this time round – albeit of a decidedly on-off nature and not enough to do a really decent job of knocking back either oilseed rape canopies or wheat disease levels.
The cold weather has certainly led to a nice frost tilth on ground set-up for spring planting before Christmas. Fingers firmly crossed, with soils drying out steadily, we could even see some barley drilling in the coming week. As ever, though, patience will be our watchword to ensure we give our crops the best possible start.
In general, N-Mins are on the low side across the region, with any nitrogen left over from last season well-used in the growthy autumn and early winter. But soils are still cold; most of our oilseed rape has a GAI of at least 1.5; and our first wheats have a good 6-7 tillers in many cases. So we’re in no rush to get any nitrogen onto most crops just yet.
Good competitive OSR stands and cold conditions have helped maximise the effectiveness of our propyzamide, carbetamide and bifenox applications. Unlike last year, for instance, charlock control has been superb.
Delayed sowing and robust residual programmes have given us good grassweed control in our wheat too. This and some useful winter weather means any black-grass is much smaller than we’ve been used to in recent years. Which means we’ve high hopes for any post-em tidy up once spring growth gets going.
Unfortunately, it hasn’t yet been cold enough for long enough to make a major impact on the early season build-up of yellow rust or Septoria in our well-grown wheats. Four weeks is a long time in agronomy – as it is in politics. But we’re gearing-up for the sort of robust T0s that stood us in such good stead last season. With the amount of disease we’ve still got in the base of many crops it looks like we’ll be needing some decent early curative activity.
The very last thing we can afford is to risk compromising the most important element of our whole fungicide programme – the T1 to T2 gap. With the shift in Septoria sensitivity and the more rapid cycling of the Warrior yellow rust race, these days a gap of three weeks or less is non-negotiable for us.
More of a dilemma – with rapeseed at just £250/t – will be balancing the effective plant growth regulation most of our OSR will need with any light leaf spot control. Thankfully, our autumn spray programme has allowed us to keep well on top of LLS so far. Long may this continue. Having to spend significantly on both disease control and PGR this spring would be a bitter pill, indeed. On the other hand, we know just how damaging both over-large canopies and LLS can be. So it may well be a pill we have to swallow to protect the yield we simply cannot afford to lose.