Improving Wheat (Triticum aestivum L.) Yield through Split Nitrogen Fertilizer Application and Optimal Row Spacing: Implications for Food Security

Abstract Background Wheat ( Triticum aestivum L.) is a globally important staple crop, and nitrogen (N) management together with plant spatial arrangement are among the most accessible agronomic levers for closing wheat yield gaps in resource-limited cropping systems. The timing of split nitrogen application, combined with row spacing, remains underexplored, particularly under the alkaline, loam-textured soils typical of the irrigated wheat belt of Punjab, Pakistan. A field experiment was conducted during the 2021–22 Rabi season at the University of Agriculture, Faisalabad, Pakistan, using wheat cultivar Akbar-19, to evaluate the combined effects of row spacing and nitrogen split-application timing on wheat yield and yield components. The experiment followed a factorial randomized complete block design with three replications, combining three row spacings (10, 15 and 20 cm) with four nitrogen split schedules: NT1 (1/3 tillering + 1/3 booting + 1/3 grain filling), NT2 (1/2 sowing + 1/2 tillering), NT3 (1/2 tillering + 1/2 booting), and NT4 (all nitrogen at tillering). Plant population, 1000-grain weight, straw yield, biological yield, grain yield and harvest index were recorded and analysed by ANOVA, with means separated by LSD at P ≤ 0.05. Results Row spacing and nitrogen split timing each significantly influenced all yield parameters, and their interaction was significant for grain yield. Widening row spacing from 10 to 20 cm increased grain yield from a treatment mean of 2207.3 kg ha⁻¹ to 4347.9 kg ha⁻¹, and the three-way split schedule (NT1) outperformed the other schedules across most parameters. The combination of 20 cm row spacing with NT1 produced the highest grain yield (4402 kg ha⁻¹), 1000-grain weight (41.77 g), biological yield (9763 kg ha⁻¹) and harvest index (45.35%), while 10 cm row spacing combined with a single tillering-stage dose (NT4) produced the lowest values across all yield traits. Conclusions Distributing nitrogen across tillering, booting and grain filling, combined with a wider 20 cm row spacing, offers a practical, input-efficient strategy for improving wheat grain yield and yield components under irrigated, alkaline-loam soil conditions. These findings suggest that meaningful yield gains are achievable through fertilizer timing and planting geometry alone, with direct relevance for smallholder food security.