Response of six-row barley to N and P2O5 fertilizer application in high fertility sites in Central Alberta

Abstract

Two series of N and P2O5 fertilizer response trials were conducted at a total of five sites in Central Alberta in 1985 and 1986 to determine whether a range of barley (Hordeum vulgare) cultivars differed in their response to high levels of fertility application under high-yielding conditions. The cultivars included were two semidwarf (Samson, Duke) and three of conventional height (Leduc, Klondike and Johnston). No cultivar × fertility level interaction was obtained for grain yield in any of the trials, although significant interactions of minor magnitude were found for other agronomic traits in some trials. The most important of these traits was extent of lodging which was at a low level (less than 3 on the 0.2–9 Belgian Scale) in all trials, despite average grain yields ranging from 4000 to 6289 kg ha−1. Lodging was more severe in Johnston than in the other cultivars. Yields of the semidwarf s were no higher than those of Leduc in any trial, although minor lodging occurred for Leduc in some cases. Lack of significant cultivar × fertility interaction may be partially explained by the general lack of response to the higher fertility levels that were used, although good yield response was found to addition of 45 kg ha−1 of P2O5 in four of six trials, and to addition of up to 90 kg ha−1 of N in three of the six trials. No significant correlation was found between initial soil test N and P2O5 versus the mean year-site yield for different locations, suggesting that factors other than base soil fertility were more important in determining site-year yield potential. These results suggest that use of individualized fertilizer recommendations for targeting maximum yield for any of the cultivars studied is not warranted, since the cultivars demonstrated similar yield responses. The excellent straw strength advantage of the semidwarf cultivars was reconfirmed under these high yielding conditions, but yields over 6000 kg ha−1 with several taller cultivars were also recorded without lodging (e.g. Leduc). Key words: Target yields, lodging, Intensive Crop Management®, cultivar specific fertilizer recommendations