Agronomic biofortification and mineral composition of teff <em>(Eragrostis teff (Zucc.)Trotter)</em> grown with different organic residue products and inorganic soil amendments

Teff (Eragrostis teff (Zucc.) Trotter) is the oldest indigenous cereal crop cultivated in Ethiopia and is gluten-free. A field experiment was conducted to evaluate the effects of various organic residue products on the agronomic characteristics of teff. The treatments included a factorial combination of five organic residues: compost (4.2 kg/plot), vermicompost (3.6 kg/plot), slurry-solid (3 liters/plot), slurry-liquid (1.5 liters/plot), and animal manure (12 g/plot). Additionally, one mineral fertilizer, NPSZnB (22 g/plot), was used along with a control group. Two teff varieties were tested: Negus and Felagot. The experiment was arranged in a randomized complete block design with three replications. Compared with those of the control treatment, the organic residue products presented positive and highly significant differences in terms of days to flowering, days to maturity, plant height, panicle length, lodging index, total biomass yield, and grain yield. However, the application of organic residue and mineral fertilization did not affect the lodging index or several off-types. The grain yield was highest for both teff varieties grown with compost and vermicompost, followed by those grown with NPSZnB, bioslurry solid, liquid, or animal manure. The lowest grain yield was observed in the control treatments for both teff varieties. However, there was no significant difference in yield between the treatments that used compost and those that used vermicompost for both varieties. A significant interaction was observed between organic residue and the different varieties of teff in terms of plant height, panicle length, total biomass, grain yield, and harvest index. Compared with the mineral and control treatments, the application of organic residue products had a more substantial effect on the yield and yield components of teff. Teff could be a good source of protein, calcium, iron and zinc which are limited in other cereals. Grain yield and mineral composition could be affected by organic residue products and variety. Therefore, further research needs to be conducted on the effect of the organic residue products on agronomic biofortification and mineral compositions of the two teff vatities.