Landscape and micronutrient fertilizer effect on agro-fortified wheat and teff grain nutrient concentration in Western Amhara.

Abstract

Abstract Agronomic biofortification, encompassing the use of mineral and organic nutrient resources to improve micronutrient concentration in staple crops, is a potential strategy to promote production and access of micronutrient-dense foods at farm-level. However, the heterogeneity of smallholder farming landscapes presents challenges on implementing agronomic biofortification. Here, we test the effects of zinc (Zn) and selenium (Se) containing fertilizer on micronutrient concentration of wheat ( Triticum aestivum L.) and teff ( Eragrostis tef (Zucc.) Trotter) grown under different landscape positions and with different micronutrient fertilizer application methods; in the western Amhara region of Ethiopia. Field experiments were established in three landscape positions at three sites, with five treatments replicated across five farms per landscape position and over two cropping seasons (2018 and 2019). Grain Zn concentration ranged from 26.6-36.4 mg kg -1 in wheat and 28.5-31.2 mg kg -1 in teff. Grain Se concentration ranged from 0.02-0.59 mg kg -1 in wheat while larger concentrations of between 1.01-1.55 mg kg -1 were attained in teff. Larger concentrations of Zn and Se were consistently attained when a foliar fertilizer was applied. Application of ⅓ nitrogen (N) yielded significantly larger grain Se concentration in wheat compared to a recommended N application rate. A moderate landscape effect on grain Zn concentration was observed in wheat but not in teff. In contrast, strong evidence of landscape effect was observed for wheat and teff grain Se concentration. There was no evidence for any interaction of the treatment contrasts with landscape position except in teff where an interaction effect between landscape position and Se application was observed. Our findings indicate an effect of Zn, Se, N, landscape position, and its interaction effect with Se on grain micronutrient concentration. Targeting of micronutrient fertilizer application in ongoing agronomic biofortification interventions is likely to be influenced by landscape position and more so by micronutrient fertilizer application method and N fertilization.