The latest UK advisory update from ADAS discusses the impact of this year’s weather on combinable crop – winter wheat, winter barley, winter oats and oilseed rape – growth rates.
A key impact noted is the lack of rain through the middle part of the year. This resulted in a number of growers delaying drilling until later in the year in the hope that sowing in October would mean higher levels of soil moisture in seed beds leading to better establishment.
The report, for the first time, assesses the condition of crops using the United States Department of Agriculture (USDA) approach, classifying crops into five categories, ranging from very poor to excellent.
The report concludes that, overall, cereal crops are in good to excellent condition; however, oilseed rape is slightly lower with 11% of the crops in a poor condition.
Report Overview
ADAS is confirming that after an exceptionally dry start to the summer, moderate rainfall during July and August helped reduce soil moisture deficits in many areas.
Drilling conditions have generally been marked by low soil moisture levels, leading to late sowing in many regions, as farmers postpone crop establishment in order to wait for soil moisture levels to rise.
As such, although winter cereal drilling started in September, it was still taking place in late November in most regions, for those who opted to postpone. Likewise, the early oilseed rape harvest meant that the drilling window opened in early August for many farmers, although, as with cereals, some farmers opted to delay drilling in the hope that soil moisture levels would increase.
Due to the dry soil conditions this autumn, there was a marked increase in the use of minimum tillage as well as direct drilling, with many farmers who would normally use inversion tillage, instead opting not to plough, in order to conserve soil moisture and reduce input costs.
Likewise, reports also suggest that many farmers took this opportunity to experiment with direct drilling for the first time.
As of the end of November, drilling is complete in all but a few crops, with just a few isolated areas of winter wheat and winter oats left to sow. The lack of soil moisture has meant that a proportion of farmers decided to delay drilling into late October or even well into November, in the hope of higher soil moisture levels in seed beds and better establishment.
Weed pressure remains relatively low overall, despite the dry soil conditions reducing the effectiveness of pre-emergence herbicides and there have been no major concerns reported, as in many incidences, the lack of moisture has also impeded weed growth.
Pest pressure
Overall, pest pressure has also been low, although warm temperatures into November have meant that aphids have remained active for a prolonged period this autumn, which has increased the risk of barley yellow dwarf virus (BYDV) spread.
Widespread cabbage stem flea beetle (CSFB) damage has been reported, in particular on late drilled crops that were not well established prior to adult migration. As such, approximately 5% of oilseed rape crops have already been lost due to a combination of slow growth due to lack of moisture and CSFB damage.
The dry autumn conditions have meant that there has been little or no slug activity, even where oilseed rape was the preceding crop.
However, aphid numbers have been high this autumn, in part due to relatively mild conditions leading to a late finish to aphid migration. As such, growers in several regions applied foliar insecticides to their earlier drilled crops, even in cases where a seed treatment had been used.
The recent drop in temperatures in November meant that later drilled crops were under lower aphid pressure.
Overall disease levels were low at the end of November. Mild conditions encouraged the development of mildew, particularly on early (September) sown crops. Recent frosts controlled most outbreaks, and few crops have required treatment to date. Septoria and rust levels remain low.
