Effect of varied N rates and N timings on yield, N uptake and fertilizer N use efficiency of a six-row and a two-row winter barley.

摘要

The effects of N rates and N timings on yield formation, N uptake at five growth stages and fertilizer N use efficiency of six-row and two-row winter barley were evaluated in field trials conducted from 1990/91 to 1992/93 at the TU Munich's researchstation Roggenstein. On average over 3 years the six-row cultivar (Tapir) yielded most at a total rate of 110 kg N ha-1 including an early application of 40 kg N ha-1 up to EC 30 (Zadoks scale). The two-row cultivar (Trixi) achieved maximum yield at a total rate of 140 kg N ha-1 including early applications of 70 kg ha-1 up to EC 30. The highest yielding N-treatments of six-row barley regularly took up less nitrogen at EC 32 (95 kg ha-1 on average) than the non-optimally fertilized treatments, whereasfull exploitation of the yield potential of two-row barley was associated with higher rates of N uptake at EC 32 (113 kg ha-1 on average). Lodging did not occur in the trials conducted in 1991 and 1992 and no difference was detected between the two cultivars in fertilizer N use efficiency. With six-row barley the N treatment giving maximum yield also led to an optimum fertilizer N use efficiency. Full exploitation of the two-row barley yield potential was associated with suboptimal fertilizer N use efficiencies.