Weed populations vary dramatically in cereals crops depending on the implementation (and success) of autumn residual herbicide programmes and cultural controls such as cultivation techniques and delayed drilling. As we wait to see when spring and a consistent rise in temperature will come, it is worth planning ahead, especially on fields with high weed pressure.
The later spring sulfonylurea herbicide applications are made, the greater the risk to crop and yield, as well as increasing pressure on actives to control larger and larger weeds. Once we are safely out of frosty conditions and high diurnal temperature ranges, we need to get these jobs done.
Crops that received routine manganese applications in the autumn have avoided deficiency symptoms thus far on all but the most susceptible land. Continue to monitor crops – the onset of symptoms can seemingly occur overnight and plants will have been affected even before visual symptoms are presented.
Manganese deficiency can cause a reduction in leaf wax, which in turn can exacerbate crop damage from herbicides; therefore remedy of deficiency must be achieved as soon as possible before spring weed control. Deficiency is hard to cure while it is cold because manganese will not be mobile in a plant that is not growing. Apply a maintenance dose now to ensure there is availability of the micronutrient as soon as crop growth starts. Follow-up with another application once the plant is growing.
As we wait for the weather to come right for establishment of spring crops it is worth remembering that waiting for the right seed-bed conditions for spring barley will be more important than getting in early, whereas with spring beans achieving optimum seed-bed conditions has to be balanced with the need for as early drilling as possible to avoid delayed harvesting and the potential for yield reductions from dry conditions during flowering.
When planning early spring nitrogen applications crop growth stage should be taken into account; forward crops may benefit from a reduced, split or delayed first application whereas small crops will have a requirement as soon as soil conditions allow and the crop is actively growing. Overall nitrogen rates on the new high yielding milling wheat varieties need to be considered – up to 60kg more N could be required to achieve 13% proteins. A four split programme will allow for flexibility depending on the season and therefore yield potential of these crops.