The effect of non-targeted application of propiconazole on the yield and quality of malt barley

Abstract

Karamanos, R. E., Flore, N. A., Harapiak, J. T. and Stevenson, F. C. 2012. The effect of non-targeted application of propiconazole on the yield and quality of malt barley. Can. J. Plant Sci. 92: 341–349. There is a desire to use non-targeted applications of foliar fungicide to improve malting barley production under higher fertility situations. An experiment was conducted at 80 sites (location by year combinations) with a 12 combinations of N/P/K rate-placement to determine if applications of propiconazole improve malt barley yield and quality under high fertility conditions. Treatment differences for days to maturity were no greater than about 1 d. Fungicide by fertility treatment interactions were not significant (P>0.05). Applications of propiconazole improved yield by 305 kg ha−1 (6%) and plump kernels by 3 g kg−1 (3%) across all fertility treatments, which included N fertilizer rates ranging from 0 to 90 kg N ha−1. The effect of fungicide on yield was greatest at sites with highest yield potentials (ca. 8000 kg ha−1) and was not statistically significant at lower-yielding sites (ca. 3000 kg ha−1). Application of propiconazole also improved net returns [barley revenue – (N cost+propiconazole cost+other operating costs)] by $22 ha−1 with higher barley priced ($190 T−1) and high yield potentials. At sites with low yield potential, the application of propiconazole resulted in net losses of about $7 ha−1 compared with not applying propiconazole. Nitrogen fertilizer rates from 0 to 90 kg N ha−1 (15/30-0 P-K fertilizer treatment combinations) increased yield and protein concentration, and reduced plump kernels in a curvilinear fashion when averaged across fungicide treatments. Net returns were maximized at N fertilizer rates slightly less than 90 kg N ha−1, depending on the price/cost regime. Consequently, malt barley producers will have to consider tradeoffs regarding N fertilizer rate that optimizes yield/returns and kernel quality. Also, decisions regarding fungicide applications and N/P/K fertilizer rate-placement applications can be made independent of each other for malt barley production.