Response of maize to irrigation and blended fertilizer levels for climate smart food production in Wolaita Zone, southern Ethiopia

Sustainable development needs climate-smart food production systems. This study examined maize responses to irrigation levels of 70, 85, and 100% crop evapotranspiration (ETc) and blended fertilizer rates of 0, 50, 100, and 150 kg ha-1, in factorial combinations. Blended fertilizer contains nitrogen, phosphorus, sulfur, and boron (NPSB). A field experiment was conducted for two seasons (2020 and 2021) in a randomized complete block design with three replications. Results indicate that the earliest tasseling (68 days), silking (73.5 days), and maturity (117 days) were recorded at the interaction effect of up to 30% deficit irrigation with 100 kg ha- 1 NPSB. In response to the interaction effect of 30% deficit irrigation with the highest fertilizer level, the highest canopy cover (2.5) and stem diameter (4.35 cm) was recorded at 70% ETc x 150 kg ha- 1 NPSB. Plants also produced the highest leaf area index (4.47) and height (2.53 m) at full irrigation level with the highest fertilizer. The highest cob length (23.4 cm), number of kernels per cob (586), thousand kernels weight (395g), biomass yield (23.27 ton ha -1), and grain yield (8.8 ton ha -1) were recorded at 100% ETc x 150 kg ha- 1 NPSB . The highest harvest index (32.33%) and fertilizer use efficiency (51.1 kg kg -1) were recorded at 85% ETc x 100 kg ha-1 NPSB, and 100% ETc x 50 kg ha- 1 NPSB, respectively. The highest water productivity was obtained in response to the main effects of 30% deficit irrigation (2.71 kg m-3) and 150 kg ha-1 NPSB (3.21 kg m-3). The future maize productivity is projected to decrease by up to 15.11% by 2030, 2050, and 2070, under two representative concentration pathways (RCP4.5 and RCP8.5). Based on the results, using 85% ETc with 100 kg ha- 1 NPSB is optimum. Policymakers and agricultural offices better consider climate-smart maize production systems in Ethiopia.