A prolonged period of hot, dry weather allowed an early start to the 2018 GB harvest. High temperatures continued throughout the harvest window although more unsettled conditions with heavier rainfall was seen during mid-August. Although the progress of harvest slowed compared to previous weeks, it continued to be just ahead of the last five harvests. After initial concerns that yields would be negatively impacted by the extended hot, dry weather they were better than expected in most areas, particularly on heavier soil types where moisture retention has been higher. Yields on lighter soil have been more variable and very much down to rainfall in each region.
Few crops have required drying, although during the middle of harvest when temperatures where highest, some crops have required ventilating to reduce the temperature before storage, although the cooler temperatures towards the end of harvest have reduced the need for this. So far, average moisture content of samples submitted for our survey is 12.6% which significantly lower than 13.9% reported last year.
ADAS (in their harvest reports for AHDB) have reported that yields for winter wheat are just below the 5 year average of 8.2 t/ha at 7.8-7.9 t/ha. For spring wheat average yields are between 5.0-6.0 t/ha with yields as high as 7.5 t/ha seen on heavier soils (adjusted to 14.5% moisture). (https://cereals.ahdb.org.uk/markets/market-news/2018/september/28/gb-harvest-progress-2018-report-6.aspx)
Specific weights have been adequate, with ADAS reporting winter wheat averaging 76 kg/hl (typical range 73-78 kg/hl) and spring wheat averaging 75 kg/hl (typical range 72-80 kg/hl) although significant variation has been seen depending on soil type. Samples collected so far for our survey indicate an average specific weight for wheat of 77.4 kg/hl although this is on a relatively small sample set.
Table 1. shows the year to year change of key nutrients based on wet chemistry and it will be interesting to see if these trends are maintained once later harvested crops have been analysed.
Wet chemistry analysis of wheat samples indicates a slight drop in the average protein of 0.2% units (adjusted to 13.5% moisture) compared to 2017 as shown in Figure 1. Unsurprisingly, regional differences have been seen with protein results highest in the central regions and lowest in the north.
When corrected to standard moisture, results from our survey indicate that energy is comparable to last year at 12.98 MJ/kg as shown in Table 2.
The winter barley harvest was complete by mid-August which is in line with progress made in 2017 and reports indicate that yields are in line with the 5 year average at 6.8-7.0 t/ha. Although there has been a great variability of yields both within and between regions. The spring barley yield is estimated to be lower than the 5 year average of 5.8 t/ha at 5.2-5.3t/ha. Specific weights are more variable than previous years with ADAS reporting an average of 64 kg/hl. Early indications of analysis on samples submitted for our survey show a slight decrease in protein of 0.2% although this should be treated with caution until samples collected from the later stages of harvest have been analysed.
Current reports indicate both wheat DON and Zearalenone levels remain low. Barley DON levels are low with patches of elevated Zearalenone levels distributed across the country.