Response of Teff ((Eragrostis tef (zucc.) Trotter) to nitrogen and phosphorus applications on different landscapes in eastern Amhara

Abstract

The dynamic nature of soil fertility status across different landscapes attracted research attention in Ethiopia and the globe. Teff [Eragrotis tef] is a major staple cereal crop in Ethiopia but yields are low due to inadequate nutrient supply and other constraints. A field study was conducted in 2020 and 2021 in the Habru district of Amhara Region to determine teff yield response to fertilizer-N and -P at hillslope, midslope, and footslope positions with slopes of >15%, 5–15%, and 0–5%, respectively. N and P fertilizer rates were factorially combined in randomized complete block design with three replications in each farmer's field. A linear mixed modeling framework was used to determine effects on grain yield due to N rate, P rate, slope, study sites, and years. Model fit was examined using Akaike's Information Criterion and Bayesian Information Criterion. Economic analysis was done with a quadratic response function to determine the economics of fertilizer. Yield response to fertilizer-P was affected by slope but the response to fertilizer-N was not affected. Teff yield increase with fertilizer-N application up to 92 kg ha−1 the economic optimum rate based on the yield response function for nitrogen fertilizer was 85.4 kg ha−1 to obtain maximum profit (86878.8 birr ha-1). Similarly, the optimum phosphorus fertilizer rate at the hill slope was 39.7 kg ha−1 to obtain a maximum profit of (96847.8 birr ha−1). But there was not a profitable response at the midslope and foot slope positions. Therefore, for Habru district and similar agroecologies85.4 kg ha−1 N and 39.7 kg ha−1 P in hillslopes and only 85.4 N kg ha−1 for midslopes and foot slopes are expected to give the most profitable returns to fertilizer applied for tef production.