Abstract
Soil fertility depletion is emerging as a serious challenge causing low crop yields and food insecurity in Ethiopia. An on-farm experiment was conducted in 2017/2018 cropping season to investigate the effects of combined application of compost and mineral fertilizer on selected soil properties and maize yield in North-western Ethiopia. Treatments were factorial combinations of three rates of Urea/NPSB (0/0, 50/50 and 100/100 kg ha(-1)) and three rates of compost (0, 5 and 10 t ha(-1)). The field experiment was arranged in randomized complete block design (RCBD) with three replications. Results showed that combined application of compost and mineral fertilizer significantly (p < 0.05) increased soil pH, organic carbon (OC), total nitrogen (TN), available phosphorus (AP), available sulphur (AS) and cation exchange capacity (CEC) compared to sole mineral fertilizer application and the control. On the other hand, there was significant (p < 0.01) decrease in soil bulk density. Plots amended with 10 t ha(-1) compost and 100/100 kg ha(-1) Urea/NPSB provided the highest maize dry biomass (18.62 t ha(-1)) and grain yield (6.07 t ha(-1)). Conversely, the lowest biomass (5.70 t ha(-1)) and grain (1.17 t ha(-1)) yields were obtained from the control. The partial budget analysis also showed that the highest net benefit (32700 Birr ha(-1)) was obtained from combined addition of organic and mineral fertilizer which was significantly higher than applying the highest rate of sole mineral fertilizer (27438 Birr ha(-1)), highest rate of sole compost (9011.3 Birr ha(-1)) and the control (7660 Birr ha(-1)). Therefore, we concluded that integrated fertilizer management improves soil properties and crop yield in the highlands of north-western Ethiopia.