Potassium application using the 4r nutrient stewardship approach for improving wheat growth and yield traits

Potassium (K) plays a key role in numerous plant metabolic processes, and its adequate amount is necessary for proper plant growth and development. Imbalanced fertilizer application has rapidly depleted the soil available K and harmed crops. However, the science-based K application in crops must follow the 4R nutrient stewardship approach to enhance crop yields. Therefore, a planned pot study used the 4R nutrient management technique for wheat potassium management. The evaluation of two wheat cultivars (Punjab-2008 and Barani-2011) employed two commercial K sources (MOP and SOP) with different application methods (basal and foliar) and sowing times (15 October, 15 November, and 15 December). The wheat variety Punjab-2008 performed better in root and shoot length, fresh biomass, and grain yield between 15 October and 15 November. Meanwhile, the Barani2011, sown on 15 November, produced higher total chlorophyll contents and water use efficiency (WUE). The use of SOP (high dose), MOP (medium to high dose), and foliar spray of SOP at 1.5% and 3% resulted in maximum shoot length and the root-to-shoot ratio for both tested cultivars. Punjab2008 produced higher grain yield when applied with a high SOP level than a high level of MOP. Similarly, a maximum leaf area index and proline contents observed in Punjab-2008 occurred with a high level of SOP applied. In contrast, a higher net photosynthesis rate and WUE emerged in Barani2011 under a medium SOP level and a higher level of MOP. Thus, the conclusion is that medium to high rates of SOP proved a better source of K nutrition for improving yield parameters of wheat cultivars.