New malting varieties now have equal or better yield potential than standard feed varieties, thanks to breeders influence on germplasm, says Ron Granger, arable technical manager for Limagrain UK. “In fact over the last ten years we have been seeing an increase on yield of 1% per year, which is substantial.”
However recognising how we grow spring barley to achieve both high yields, and meet contractual specifications of the chosen end market is crucial to success, he adds.
“Through Limagrain’s investment in trials, both internally and externally, we evaluate the agronomic requirements of the spring barley crop and the subtle differences between varieties, ensuring both high yield and end use specifications are met.”
Seed rate
Limagrain does not advise definitive seed rates for spring barley and can only suggest suitable seeding rates, based on the breeder’s knowledge of the variety gained through both plot and field trials.
“We have carried out trials for three consecutive years looking at both drilling date and sowing rates across Scotland and the rest of the UK to determine optimum seed rate figures.”
“This work has found that a starting point of 350 seeds/m2 appears to be the optimum for most varieties in ideal growing conditions. This figure can then be either decreased or increased depending on the situation as outlined previously and this would concur with standard seed rates of around 325 – 375 being used by growers on farm today.”
“Drilling date would certainly appear to have an influence on final potential yield, but it’s important to stress that very early drilling should only be pursued if weather and soil conditions, including temperature, allow for good germination and plant establishment are ideal.”
“Patience is a virtue especially regarding the sowing of any spring crop – waiting until conditions are favourable is essential.”
Tiller Counts
The target final tiller number in the AHDB Barley Growth Guide is 775/m2 (3 shoots /plant), looking at both trials and farm plant populations this appears to be underachieved in many situations, suggesting that full yield potential is not being reached,” says Mr Granger.
Establishing and more importantly securing a final tiller count of around 775/m2 will ensure full yield potential, is his advice.
“We have been recording tiller counts for several years in Scotland; the data very strongly indicates that newer varieties such as Octavia, Sienna and Ovation are producing higher tiller counts, with the benefit of increased yield.”
He also points out that varieties with higher tiller counts show benefits in situations of stress, i.e. drought, showing that they will compensate where plant numbers are low. Whereas low tillering varieties are limited in their capacity to compensate.
“Our trials have shown that final tiller counts can be pushed over 1000/m2 in very fertile soil conditions, but results would suggest no additional yield performance over the 750/m2 final tiller target. Additionally it can lead to negative agronomic traits being induced, such as lower specific weights, higher screenings, additional lodging pressure and increased disease pressure.”
Nitrogen interaction
Limagrain has a theory that if spring barley yields have increased by more than 10%, perhaps the conventional approach to the fertiliser regime should be investigated, to see if additional yield performance can be obtained with higher rates of nitrogen.
“This is not straight forward as the final grain nitrogen percentage cannot be compromised, especially if growing for the malt distilling market which requires a low grain nitrogen content, says Mr Granger.
Higher grain nitrogen levels required by the brewing and grain distilling contracts should offer opportunities for driving for additional yield potential with higher rates of nitrogen, while still achieving the specific grain nitrogen percentage.
Limagrain has been conducting trials work looking at variety interaction with differing nitrogen rates in some detail over the last couple of seasons. The following data is from a trial done in conjunction with Scottish Agronomy looking at two nitrogen inputs over a range of Limagrain varieties.
“Two nitrogen inputs were tested, 120 kg/ha in total applied in the seed bed, supported by an additional 30 kg applied at tillering, making a total input of 150 kg/ha.”
“The result was an additional 0.4 – 0.5 t/ha yield across the varieties. This is significant certainly in a commercial situation, but this has to be compared with the actual grain nitrogen percentage figures. “
Chart 3 Variety / Nitrogen interaction – Yield
Chart 3 shows the additional yield performance associated with the extra 30 kg/ha applied over the standard seed bed application of 120 kg/ha.
Chart 4 Variety / Nitrogen interaction – Grain nitrogen %
“Interestingly the grain nitrogen percentage did not increase significantly, remaining well within the contract specification of below 1.65% grain nitrogen for malt distilling contracts. One could argue that the additional yield had a dilution effect on the final grain nitrogen percentage as anticipated. “
“We should also take into account that grain data from both internal and external trials during 2016 confirm that it was a season of lower grain nitrogen accumulation levels, highlighting the importance of continuing trials over several seasons.”