The effects of biochar, compost and their mixture and nitrogen fertilizer on yield and nitrogen use efficiency of barley grown on a Nitisol in the highlands of Ethiopia

Agronomic efficiency (AE) and apparent nitrogen recovery efficiency (ARE) of barley under organic amendments (Con: control, B: biochar, Com: compost, Com + B and COMBI: co-composted biochar) and N fertilization at Holetta (upper half) and Robgebeya (lower half) sites of contrasting soil fertility levels.226