Nutritional and Physiological Significance of Potassium Application in Maize Hybrid Crop Production

Maize is a particular cereal crop which is more affected by variations in plant density than other members of the grass family, due to its low tillering ability, its monoecious floral organization and the presence of a brief flowering period. Different maize cultivars respond differently to K application under varying plant densities, due to different root/shoot ratio, growth rate, crowding stress tolerance, intra-specific competition between plants, K uptake and utilization. Maize cultivars have the ability to withstand high plant density due to more partitioning of assilimilates to shoot as compare to root, resulting in reduction of root/shoot ratio. K application reduces the percent of senescent stalks, lodging and increased crushing strength and rind thickness. There is general consensus that the soils of Pakistan have large capacity to provide K to crop under ordinary conditions, but the increase in the intensity of cropping, excessive use of the tube well water, introduction of the high yielding cultivars requiring high K, increasing use of N and P, could hasten the removal of K from the soils and imbalance the uptake of K in relation to other nutrients. Genotypic and crop species differences exist in response to soil and fertilizer K and non-yield traits such as stalk strength or product quality must be taken into account in K management decisions. K application not only increases grain yield, but also improves quality parameters. K application improves utilization of water, tolerance to drought through stomatal conductance, acceleration in photosynthesis process, water up take through roots. Its application improves leaf area, dry matter accumulation and other allometric parameters. K in combination with N has synergistic influence in uptake, translocation and utilization of nutrients for assimilation in growth and development of final grain yield and its contributing attributes. Normally K deficiency symptoms are usually not conspicuous although grain yield is abruptly decreased (called hidden hunger), but severe deficiency do express symptoms. It is therefore suggested that luxuriant application of K is inevitable for getting successful and maximum production from maize hybrids.