Effect of nutrient omissions on bread wheat and tef crops grain yield in Western Amhara, Ethiopia

The decline in soil nutrients in Ethiopia, particularly in Western Amhara, is causing low crop productivity. Some researchers have argued that the application of K, S, Zn, and B in blended, individual, and complex forms affects crop yield. Identification of the prime yield-limiting nutrient is the key to solvesoil nutrient problems. A field experiment was conducted at Burie-Wemeberema, Debere Elias, Gozamen and Gonji Qolela districts of Western Amhara in the 2022 cropping season. A composite soil sample was taken at a depth of 0-20 cm to determine soil chemical properties. Bread wheat and tef were used as a test crop. The gross plot sizes were 4m x 3m and the spacing between blocks and rows was 1.0 and 0.2 m, respectively. The experiment was laid out in a randomized complete block design with three replications and comprised of nine treatments: control, NPKSZnB-blended, NPKZnB, NPKSB, NPKSZnB, NPSZnB, NP, NPKSZnB-individually applied, and NPSZnB-compound+K. R programming software version 4.2.2 was used for data analysis, and treatment means were separated at P < 0.05 using the LSD test. The analysis of variance results showed that nitrogen and phosphorus are the most yield-limiting nutrients so far in the study area. Besides, omissions of potassium, sulfur, zinc, and boron did not show a significant (P < 0.05) effect on bread wheat and tef grain yield reduction as compared to the applied recommended nitrogen and phosphorus at all landscape positions of all study sites. Blended and compound nutrients also didn't show a significant grain yield advantage as compared to the applied NP nutrients. Applied potassium, sulfur, zinc, and boron nutrients in blended, individual, and compound forms did not increase wheat and tef grain and biomass yields in all study areas. Currently, additions of K, S, Zn, and B nutrients in the fertilizer package do not have a significant grain yield advantage as compared to the recommended NP nutrients. We believe the present information on fertilizers in blended, compound, and individual forms is insufficient to draw any concrete conclusions. Therefore, we suggested further research to confirm which form of fertilizer and nutrient source is better for future crop production.