Nitrogen use efficiency of maize and spring barley under potassium fertilization in long-term field experiment

In the paper, the results of the long-term field experiment on soil depletion from potassium on yields and selected indices of nitrogen use efficiency of maize and spring barley were presented. The factors of the experiment were potassium fertilization (K plus and K minus treatment) and increasing nitrogen rates. Maize responded for soil exhausting from K in yield reduction over all the range of nitrogen rates applied in the experiment, and spring barley only through the highest rates. The greater values of nitrogen use efficiency indices were proven for barley as compared with maize. Potassium fertilization slightly increased agronomic efficiency and physiological efficiency of barley.