Optimization of Plant Spacing and Fertilizer Inputs for Enhanced Teff Productivity and Nutrient-Use Efficiency

Background: Teff (Eragrostis tef (Zucc.) Trotter) is an underutilised cereal crop with potential for diversification of dryland farming systems due to its adaptability and nutritional value. However, standardised agronomic recommendations for teff cultivation in India remain limited, particularly regarding optimal planting geometry and fertiliser management for improving crop productivity and nutrient-use efficiency. Aims: To evaluate the effects of planting geometry and nutrient management on teff yield, nutrient-use efficiency, and post-harvest soil chemical properties to develop suitable agronomic recommendations. Study Design: Factorial randomised block design with ten treatment combinations and three replications. Place and Duration of Study: Zonal Agricultural Research Station, Gandhi Krishi Vignana Kendra, University of Agricultural Sciences, Bengaluru, Karnataka, India, during the Kharif season of 2021. Methodology: The experiment comprised two planting geometries (30 × 10 cm and 45 × 10 cm) and five nutrient treatments: 50%, 75%, 100%, and 125% of the recommended dose of fertilisers (RDF; 20:20:20 kg ha-1 of N: P2O5:K2O) and an absolute control. Farmyard manure (FYM) was applied at 6 t ha-1 to all treatments except the absolute control. Brown-seeded teff was harvested at 110 days after sowing. Yield parameters, nutrient-use efficiencies, and post-harvest soil pH, electrical conductivity, and organic carbon were assessed. Data were analysed using analysis of variance at the 5% significance level. Results: Planting geometry significantly influenced grain and straw yields. Narrow spacing (30 × 10 cm) recorded higher grain (2.37 q ha-1) and straw (3.65 q ha-1) yields than wider spacing (2.04 and 3.34 q ha-1, respectively). Among nutrient treatments, 100% RDF produced the highest grain yield (2.73 q ha-1), whereas 125% RDF recorded the highest straw yield (4.36 q ha-1). Test weight and harvest index were not significantly affected. Agronomic efficiency and phosphorus physiological efficiency were highest under 100% RDF, reaching 5.00 and 4.81 kg kg-1, respectively, at 30 × 10 cm spacing and 4.95 and 4.87 kg kg-1, respectively, at 45 × 10 cm spacing. Nitrogen recovery efficiency peaked under 125% RDF at 12.31% and 14.73% for the two respective spacings. Treatment interactions did not significantly affect grain or straw yield. Soil pH, electrical conductivity, and organic carbon were not significantly affected. Conclusion: Planting teff at 30 × 10 cm with 100% RDF and FYM at 6 t ha-1 may offer a suitable strategy for improving grain yield and nutrient-use efficiency in the Eastern Dry Zone of Karnataka (Zone-V).