Nitrogen efficiency of spring barley in long-term experiment

摘要

The aim of this study was to evaluate nitrogen (N) efficiency from different organic and mineral fertilizers applied to the spring barley. Dry matter yield, N content and N uptake of spring barley from 16 years of experiments at two sites in the Czech Republic with different soil and climatic conditions were analyzed. For assessing of nitrogen efficiency nitrogen utilization efficiency (NUtE, kg/kg), recovery efficiency of applied N (%), agronomic efficiency of applied N (kg/kg) and summary N balances (Sigma Delta N, kg/ha) were observed. Six fertilization treatments were utilized: no fertilization (control); sewage sludge; farmyard manure (FYM); N in mineral fertilizers (N); NPK in mineral fertilizers (NPK) and N in mineral fertilizers + straw (N + ST). Yields were about 68% higher at NPK (S1 site) and 55% at N + ST (S2 site) in comparison with control. The highest NUtE was recorded at both locations after application of FYM. Higher NUtE from mineral fertilizers was obtained at low productive S1 site. At both sites a trend of decreasing Sigma Delta N over time was observed. At both sites a trend of decreasing negative N balance was observed. At lower productive site the decline of N balance was minimized for mineral fertilizers treatments in last experimental years. At higher productive site the differences between treatments with mineral nitrogen and control were lower and the decline of N balance continued over all 16 years of experiment duration