Nitrogen indicators, uptake and utilization efficiency in a maize and barley rotation cropped at different levels and sources of N fertilization

A 3-year experiment was carried out in Mediterranean conditions on two maize–barley rotations to determine the effect of different levels and sources of nitrogen (N) fertilizer on the N uptake, efficiency, soil N deficit and crops yield. The potential for N savings by the use of N indicators was also studied. Five strategies of maize N fertilization were compared on plots laid out in a complete randomized design with three blocks: mineral N (200...