Magnesium Fertilization Improves Grain Yield of Wheat (Triticum Aestivum L.) Across Fourteen Agro-Climatic Zones of Punjab, Pakistan

Abstract

Wheat (Triticum aestivum L.) is the major Rabi cereal crop of Pakistan, but farm-level yields remain below the potential of improved cultivars. Although nitrogen, phosphorus, and potassium responses are well documented, the role of magnesium in wheat productivity across Punjab’s agro-climatic zones remains insufficiently explored. Objective: To evaluate the grain yield response of spring wheat cultivar Dilkash-2021 to graded levels of soil-applied magnesium across fourteen agro-climatic zones of Punjab, Pakistan. Methods: A multi-location field experiment was conducted under the Soil Fertility Punjab research project SF-76 during the Rabi 2024–25 season across fourteen agro-climatic zones of Punjab, Pakistan. Spring wheat cultivar Dilkash-2021 was grown using a randomized complete block design with three replications at each site. Five magnesium treatments, comprising 0, 15, 30, 45, and 60 kg Mg ha⁻¹, were applied as magnesium sulphate heptahydrate (MgSO₄·7H₂O) through basal broadcast application. All plots received a uniform basal NPK dose of 160–114–60 kg ha⁻¹. Grain yield was recorded at maturity, and data were analyzed using two-factor combined analysis of variance to determine the effects of magnesium treatment, location, and location × treatment interaction. Results: Magnesium fertilization significantly improved wheat grain yield across the study locations. The treatment effect was highly significant (F = 23.60, p < 0.01), and the location effect was also highly significant (F = 277.74, p < 0.01). The location × treatment interaction was non-significant (F = 1.34, p = 0.099), indicating a broadly consistent response pattern across the fourteen agro-climatic zones. Pooled grain yield increased from 5037.2 kg ha⁻¹ in the magnesium control to 5483.6 kg ha⁻¹ at 60 kg Mg ha⁻¹, showing a mean yield gain of 446.4 kg ha⁻¹, equivalent to an 8.9% increase over the NPK-fertilized control. The highest pooled yield was recorded at 60 kg Mg ha⁻¹, while site-wise yield differences at this rate ranged from −145 kg ha⁻¹ at Sahiwal to +1105 kg ha⁻¹ at Sheikhupura. Conclusion: Soil-applied magnesium significantly enhanced wheat grain yield under Punjab’s diverse agro-climatic conditions, with 60 kg Mg ha⁻¹ producing the highest pooled yield response. These findings support the inclusion of magnesium fertilization as a complementary component of the existing NPK schedule for spring wheat production in Punjab.