Thomas Turkington (1), Michael Edney (2), Marta Izydorczyk (3), John O’Donovan (1); (1) Agriculture and Agri-Food Canada, Lacombe, AB, Canada; (2) Malting Barley Quality Lab, Canadian Grain Commission, Winnipeg, MB, Canada (retired); (3) Canadian Grain Commission, Winnipeg, MB, Canada

Malt and Grains

Little information exists regarding the effect of previous crop residue type, nitrogen fertilizer rate and fungicide, and especially their potential interactions in relation to productivity, kernel quality, and malting quality parameters. The objective of this study was to determine the effects of these factors on productivity, kernel quality, and malting quality of the malting barley cultivar AC Metcalfe. Residue type had a significant effect on leaf disease severity, which was increased when barley was the previous crop compared with canola and field peas. In general, emergence, head counts, grain yield, kernel weight, test weight, and kernel plumpness were lowest for barley grown on barley residue compared to canola and field pea residue. Fungicide application reduced leaf disease severity and increased yield, kernel weight, test weight, and kernel plumpness, while decreasing dockage and thins. However, the magnitude of the impact of fungicide on one or more of these parameters was lower compared with planting barley on field pea or canola residue. Overall, increasing the nitrogen fertilizer (N) rate from 50 to 100% of soil test recommendation had no effect on leaf disease levels and only increased yields slightly compared to not planting barley on barley residue. However, the 100% rate of N did significantly increase grain protein levels. In contrast, planting barley on field pea residue did not result in a consistent increase in grain protein. In terms of malting quality, larger kernels were produced when barley was grown on canola or peas versus barley, resulting in a less well-modified malt, but malt extract was not affected. Changes to processing would improve modification which could increase malt extract. Fungicides produced larger kernels, but malt quality was less affected. Increasing nitrogen rates produced higher grain protein, which reduced malt extract and friability but increased the levels of starch-degrading enzymes. Grain protein tended to be higher in barley grown on peas versus on canola or barley, which restricted modification but not malt extract. However, slight changes to processing would produce a malt of acceptable quality. Kernel color was affected by treatment, which may indicate a lower microbial load on barley with less disease. This would be beneficial for malting and brewing but needs further investigation. In conclusion, controlling disease with crop rotation or fungicides resulted in barley that, with slight adjustments to processing, could produce a malt of superior quality. Producers, therefore, can benefit from crop rotation and fungicide to control disease, improve yields, and yet deliver an acceptable product to the malting and brewing industries.

Thomas (Kelly) Turkington is a plant pathologist with Agriculture and Agri-Food Canada (AAFC), in Lacombe, AB, and is part of the joint Alberta/Canada Barley Development Group. He received a B.S. degree in agriculture and agricultural biology in 1985 and M.S. and Ph.D. degrees in plant pathology from the Department of Biology at the University of Saskatchewan. Kelly’s main focus at Lacombe is on barley, wheat, and canola diseases as part of collaborative studies with colleagues across Canada. As a plant pathologist, Kelly works with a range of colleagues, including research agronomists, weed scientists, plant breeders, malt quality researchers at the Canadian Grain Commission, and the malting industry to develop malt barley production strategies that improve crop health, increase productivity, and improve the quality of the harvested grain for malting and brewing.