Evaluation of Nitrogen use Efficiency and Internal Efficiency of Three Sesame (Sesamum Indicum L.) Varieties in the Sudan Savanna Zone of Nigeria

Abstract

Nitrogen use efficiency (NUE) is a critical determinant of sustainable sesame production in the Sudan Savanna zone of Nigeria. This study evaluated the nitrogen use efficiency and internal nitrogen efficiency of three prominent sesame varieties (Yandev-55, E-8, and NCRI-Ben-01M) under varying nitrogen application rates (0, 30, 60, and 90 kg N ha⁻¹). Field experiments were conducted during the 2025 cropping season at two locations: Bayero University Kano (11.9758°N, 8.5380°E) and a farmers' field in Kura Local Government Area (11.7753°N, 8.4339°E). The experiment was laid out in a split-plot arrangement in a randomized complete block design with four replications. Varieties were assigned to main plots while nitrogen levels constituted the sub-plots. Results showed that nitrogen application significantly (P < 0.001) influenced grain yield, with mean yields ranging from 727-952 kg ha⁻¹ across sites and treatments. Variety Yandev-55 consistently produced the highest grain yields (857-934 kg ha⁻¹), followed by E-8 (821-896 kg ha⁻¹) and NCRI-Ben-01M (779-878 kg ha⁻¹). Agronomic efficiency (AE) decreased with increasing nitrogen rates, ranging from 2.81 kg kg⁻¹ at 30 kg N ha⁻¹ to 1.41 kg kg⁻¹ at 90 kg N ha⁻¹. Apparent nitrogen recovery (ANR) averaged 43-45% across varieties and nitrogen levels. Physiological efficiency (PE) showed a declining trend from 6.84 kg kg⁻¹ at 30 kg N ha⁻¹ to 3.16 kg kg⁻¹ at 90 kg N ha⁻¹. Internal nitrogen efficiency (IE) was highest at 30 kg N ha⁻¹ (23.20 kg kg⁻¹) and lowest at 90 kg N ha⁻¹ (13.91 kg kg⁻¹). Quadratic regression analysis revealed optimum nitrogen rates of 98.4, 81.7, and 68.7 kg N ha⁻¹ for Yandev-55, E-8, and NCRI-Ben-01M, respectively. The study demonstrates that moderate nitrogen application (60-80 kg N ha⁻¹) optimizes grain yield while maintaining reasonable NUE in sesame production. Variety Yandev-55 exhibited superior performance in both yield potential and nitrogen use efficiency. These findings provide crucial information for developing nitrogen management strategies for sustainable sesame production in the Sudan Savanna agroecological zone.