Jeremy Curry1, Blakely Paynter2, Stacey Hansch2, Andrew van Burgel3
1 Department of Primary Industries and Regional Development, Melijinup Road, Esperance, WA, 6450 firstname.lastname@example.org
2 Department of Primary Industries and Regional Development, 75 York Road, Northam, WA, 6401
3 Department of Primary Industries and Regional Development, 444 Albany Hwy, Albany, WA, 6330
Low grain protein can cause downgrading of barley from Malt1 (GIWA Malt1 protein window is 9.5-12.8%). With increasing productivity and decreasing nitrogen (N) supply available from the soil (primarily due to lack of legumes in the crop rotation), growers need to increase their fertiliser N applications to produce adequate protein levels. In addition to increasing N rate, growers can improve their fertiliser effectiveness by changing the timing of N application. In this study, shifting N from seeding and mid-tillering to the stem elongation period consistently increased grain protein, although was often associated with increased screenings and for some treatments reduced grain yield. Most delayed N strategies (except N timings 2 and 4) provided a protein increase of 0.5-1.0% relative to the strategy of ⅓ N at seeding, mid tillering and stem elongation (N timing 1 – current practice control) in at least three of the four sites. Only two delayed N strategies, N timing 2 and 3, did not affect grain yield at any site. Compared to N timing 1 moving the ⅓ N from mid-tillering to stem elongation (N timing 2) increased grain protein at only two sites whereas applying the bulk of the N at stem elongation (N timing 3) increased grain protein at all four sites. Both strategies, however, increased screenings (at two and three sites respectively), though did not negatively impact on hectolitre weight or grain brightness. The grain protein increase of the other delayed N strategies may often have been larger than N timings 2 and 3 but came at a risk of higher screenings, lower hectolitre weight or lower grain yield (site specific). The best of the other strategies evaluated was N timing 10 (⅓ N at seeding, stem elongation and flag leaf emergence), which increased protein at three sites, had no impact on screenings or hectolitre weight at any site, although did reduce yield and brightness at one site.