ABSTRACT
Major turfgrass species (Table 33.1) are in the grass family, which includes major agricultural crops such as rice (Oryza sativa L.), wheat (Triticum aestivum L.), corn (Zea mays L.), sorghum (Sorghum bicolor [L.] Moench), barley (Hordeum vulgare L.), rye (Secale cereale L.), and other forage crops. Unlike legumes, most gasses cannot fi x N through N fi xation, and N is one of the most limiting factors for any types of grass production for yields, forage, or recreational and functional ground covers as turfgrasses [25,27,28,325,492]. By comparison with other crops, turfgrasses relatively require much less N but it is still needed in the largest quantity than any other essential mineral nutrients [95,223,224]. Turfgrass quality can be enhanced by proper N application with adequate chlorophyll content, stress and pest resistance, and shoot and root growth under different levels of maintenance to meet the turf use. Reviews on turfgrass N use, physiology, and impacts to the environment have been well documented in the last two decades [95,115,159,223,224,325,379, 494,513]. However, reviews and research in areas such as turfgrass N use and performance under stressful conditions are rather limited. Therefore, this chapter focuses on enhancing turfgrass N use under major stressful conditions.
