Spring 2016 appears to be on hold at the moment. Vigorous growth has barely started. Indeed, depredations by pigeons means some oilseed rape is going backwards. We can only hope that the weekends rain and some warmer weather moving into April will finally kick things on.
There is some consolation in the fact that disease levels, except light leaf spot in rape, have been held back. At least we do not appear to have high infestations of cabbage stem flea beetle larvae in our rape crops.
Only a minority of very forward hybrid barley in fertile situations has received an extra fungicide in advance of the usual growth stage (GS) 30/31 (final leaf 4) treatments. Early nitrogen has most definitely helped in the barley. New growth is green and healthy so we should secure good tiller survival. I believe this is as important for conventional line-bred varieties as it is for hybrids.
Understanding of nitrogen rates for winter barley continues to grow as data becomes available from AHDB funded studies. It seems that for yields in excess of 8t/ha, an extra 27kg of N per per tonne of yield is required. Extra early N does boost straw yield and height so careful thought must be given to plant growth regulator (PGR) strategies.
While high yielding, early maturing winter barley has obvious management attractions the bugbear of low prices and very difficult blackgrass control tempers the benefits. Avadex (tri-allate) and flufenacet pre-emergence applications have been essential in winter barley where there is any degree of blackgrass infestation.
Winter wheat is still at late tillering. Rusts and mildew are scarce, so GS 30/31 sprays will be geared towards straight chlorothalonil or mixes with a rust active triazole or azoxystrobin for susceptible varieties. This will be combined with chlormequat and manganese where necessary.
Be careful to take into account revised maximum doses and timings on your chosen chlormequat product. At this stage we see little need for more expensive PGRs given how slow growth is. We will reconsider at GS 32 (final leaf 3) whether or not we beef things up.
Winter oats have not ventured beyond tillering. A few over wintered broad-leaved weeds, mainly speedwells and cleavers, are being tidied up with carfentrazone and CMPP.
An indication of how unfavourable for growth March has been is that the late-drilled wheat I mentioned in my last post has barely broken the soil surface. Reports continue to pour in of spring cereal seed-beds which are dry in the top few inches, but like dough further down. Rolling heavy land in these conditions will leave season long wheel marks.
On lighter soils drilling has proceeded much more favourably. The bulk of the spring bean crop is now in the ground and pre-emergence treatments based on clomazone, linuron and pendimethalin applied.
Complying with the 250 litres of water and coarse spray requirement for clomazone has been arduous. Lack of compliance will simply stir up more anti crop protection grumblings. Clomazone drift is easy to see – it turns hedgerow plants white.