Maize Genomics and Genetics 2025, Vol.16, No.1, 20-33 http://cropscipublisher.com/index.php/mgg 24 Figure 2 Effects of N treatments on photosynthetic rate of ear leaves in maize in 2016 and 2019. One-way analysis of variance with Duncan’s new multiple range test was conducted to assess the statistical patterns (Adopted from Deng et al., 2023) Image caption: Different letters indicate a significant difference (P<0.05) (Adopted from Deng et al., 2023) 5 Rational Application of Phosphorus and Potassium 5.1 Supportive role of phosphorus in root development and early growth Phosphorus (P) plays a crucial role in the early stages of maize growth by enhancing root development and overall plant vigor. Studies have shown that optimal P fertilization significantly increases root weight, root number, and biomass, which are essential for nutrient uptake and plant stability. For instance, a field experiment demonstrated that positioning P fertilizer closer to the root zone (5 cm) improved root growth and maize yield compared to a 10 cm distance, highlighting the importance of strategic P placement (Wang et al., 2023). Additionally, P application has been found to maximize the leaf area index (LAI) and photosynthetic rate, which are critical for achieving high grain yields in summer maize (Zhang et al., 2018). Moreover, the synchronization of P application methods and rates can further enhance root development. Research indicates that foliar application of P at critical growth stages, such as knee height and tasseling, significantly boosts grain yield and phosphorus use efficiency (PUE) in maize (Rafiullah et al., 2020). This method ensures that P is readily available during key developmental phases, thereby supporting robust root growth and early plant development. 5.2 Contribution of potassium in enhancing stress resistance and improving yield quality Potassium (K) is vital for improving maize's stress resistance and yield quality, particularly under challenging environmental conditions. K management has been shown to enhance growth and yield components of maize, especially under moisture stress conditions. Field experiments revealed that foliar K application at rates of 1%~3% during the vegetative stage resulted in better growth and higher yields compared to late-stage applications (Amanullah et al., 2016). This suggests that timely K application can significantly mitigate the adverse effects of moisture stress. Furthermore, the combined use of organic amendments like biochar with inorganic K fertilizers has been found to improve maize's defensive systems and nutrient uptake. This combination not only enhances yield quantity and quality but also increases the plant's resilience to drought conditions by improving nitrogen use efficiency and reducing oxidative stress (El-Syed et al., 2023). These findings underscore the importance of K in bolstering maize's ability to withstand environmental stresses and produce high-quality yields. 5.3 Best application rates and timing for phosphorus and potassium fertilizers Determining the optimal application rates and timing for P and K fertilizers is essential for maximizing maize productivity. Research indicates that a P application rate of 90 kg/ha~135 kg/ha is optimal for maize grown in saline-alkali soils, as it maximizes grain yield and nutrient uptake without causing excessive nutrient accumulation (Ma et al., 2023). Additionally, localized application of P combined with ammonium has been shown to significantly improve nutrient uptake and plant growth by stimulating root proliferation and rhizosphere acidification (Jing et al., 2010).
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