Biomass and essential oil production of hops cv Chinook in response to nitrogen fertilization

Resumo

Hop (Humulus lupulus L.) is one of the most important raw materials of beer production. Despite being the third-largest producer and consumer of beer worldwide, Brazil imports almost all hops for production. Nitrogen is an essential macronutrient for hop development and its behavior under different doses is still unknown for Brazilian conditions. Our goal was to evaluate the dry matter and essential oil yields of the Chinook hop fertilized with five N rates during three harvests. Leaves, branches, and cones were sampled to determine their dry matter production, and cones were also analyzed for essential oil contents, extracted by hydrodistillation. Cone number per plant, cone, branch, and leaf dry matter yields, as well as total essential oil yield per plant, increased linearly as nitrogen rates were raised. The production of DM of cones obtained ranged between 245.8 (N:0) and 386.7 kg ha^-1 (N:250 kg N ha^-1). Yield differences were also noted between harvest years due to weather conditions. Therefore, we can conclude that increasing N rates and climatic conditions affect N contents in hop leaves, as well as hops overall and oil yields, due to the higher cone dry matter. However, essential oil contents in cone dry matter did not change.