*Article* **Effects of Environmental Stresses (Heat, Salt, Waterlogging) on Grain Yield and Associated Traits of Wheat under Application of Sulfur-Coated Urea**

**Adil Altaf 1, Xinkai Zhu 1,2,3,\*, Min Zhu 1,2,\*, Ma Quan 1, Sana Irshad 4, Dongyi Xu 1, Muhammad Aleem 5, Xinbo Zhang 1, Sadia Gull 6, Fujian Li 1, Amir Zaman Shah <sup>6</sup> and Ahmad Zada <sup>7</sup>**


**Abstract:** Abiotic stresses, such as heat, salt, waterlogging, and multiple-stress environments have significantly reduced wheat production in recent decades. There is a need to use effective strategies for overcoming crop losses due to these abiotic stresses. Fertilizer-based approaches are readily available and can be managed in all farming communities. This research revealed the effects of sulfur-coated urea (SCU, 130 kg ha−1, release time of 120 days) on wheat crops under heat, salt, waterlogging, and combined-stress climatic conditions. The research was done using a completely randomized design with three replicates. The results revealed that SCU at a rate of 130 kg of N ha−<sup>1</sup> showed a significantly (*p* ≤ 0.05) high SPAD value (55) in the case of waterlogging stress, while it was the lowest (31) in the case of heat stress; the control had a SPAD value of 58. Stress application significantly (*<sup>p</sup>* <sup>≤</sup> 0.05) reduced the leaf area and was the highest in control (1898 cm2), followed by salt stress (1509 cm2), waterlogging (1478 cm2), and heat stress (1298 cm2). A significantly (*<sup>p</sup>* <sup>≤</sup> 0.05) lowest crop yield was observed in the case of heat stress (3623.47 kg ha<sup>−</sup>1) among all stresses, while it was 10,270 kg ha−<sup>1</sup> in control and was reduced up to 35% after the application of heat stress. Among all stresses, the salt stress showed the highest crop yield of 5473.16 kg ha<sup>−</sup>1. A significant correlation was observed among growth rate, spike length, yield, and physiological constraints with N content in the soil. The SCU fertilizer was the least effective against heat stress but could tolerate salt stress in wheat plants. The findings suggested the feasibility of adding SCU as an alternative to normal urea to alleviate salt stresses and improve wheat crop growth and yield traits. For heat stress tolerance, the applicability of SCU with a longer release period of ~180 days is recommended as a future prospect for study.

**Keywords:** abiotic stresses; winter wheat; photosynthetic activity; morphological parameters; controlled-release nitrogen fertilizer

**Citation:** Altaf, A.; Zhu, X.; Zhu, M.; Quan, M.; Irshad, S.; Xu, D.; Aleem, M.; Zhang, X.; Gull, S.; Li, F.; et al. Effects of Environmental Stresses (Heat, Salt, Waterlogging) on Grain Yield and Associated Traits of Wheat under Application of Sulfur-Coated Urea. *Agronomy* **2021**, *11*, 2340. https://doi.org/10.3390/ agronomy11112340

Academic Editor: Juan M. Ruiz

Received: 26 October 2021 Accepted: 15 November 2021 Published: 19 November 2021

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