Optimizing planting density and nitrogen input for improved nitrogen use efficiency, yield and seed quality in sesame

Maximizing crop yield per unit area under minimal fertilizer input is crucial with minimal fertilizer input is crucial to achieving sustainable agriculture. Although dense planting has been adopted by some sesame farmers to improve yield, the practice lacks optimization. Hence, this study was conducted to determine an optimal planting density (PD) and nitrogen (N) application rate for enhancing sustainable sesame production and quality. We simultaneously investigated the impacts of PD and N-dose on sesame nitrogen use efficiency (NUE), biomass production, N allocation to organs, and seed yield and quality. Through field experiments under different PDs and N supplies and statistical analyses, we identified 190,000 plants·hm ^− 2 (PD) and 60 kg·hm ^− 2 (N-dose) as optimal conditions for sustainable improvement of sesame production. Notably, sesame yield, NUE, biomass accumulation, and seed quality traits, including protein content, fat content, and fatty acid composition, were maximal under these optimal conditions. The nitrogen allocated to seeds under these optimal conditions was significantly higher than that to stems, leaves, and capsules. Correlation analysis revealed that PD is significantly negatively associated with the number of capsules, seed number per capsule, 1000-seed weight, protein content, and linoleic acid content. N rate exhibited a significant positive correlation with protein content, total biomass, and total N content, as well as a significant negative correlation with NUE. Our findings may guide land-use efficiency for sesame farming systems and contribute to the sustainable production of high-quality sesame.