ABSTRACT
The use of turfgrasses plays an important role in designing urban areas and sport facilities. The major goal of turfgrass management programs that needs to be carried out properly is to produce beautiful, appealing, attractive, and healthy turfgrasses. On the other hand, turfgrass areas are designed to resist trafc. Turfgrass nutrition, which through adequate fertilization, is one of the most important components of a turfgrass management program. Fertilization greatly affects turf quality, including color, density, and uniformity. Turfgrass managers need to meet two apparently opposite demands and typically use high-nutrient fertilizers in an attempt to maximize turfgrass quality: (1) the demands of the users (athletes need to play and enjoy high-quality turfgrasses and amblers desire to see a well-manicured turf) and (2) ecological concerns. In addition, fertilized turfgrasses normally compete with weed invasions more efciently and are able to recover from damages imposed by stresses than improper fertilized turfs. However, high-input fertilization programs normally lead to some side effects. From an environmental point of view, high toxicity to soil, high leaching potential, and suppressing impact on soil microorganisms are important issues. On the other hand, this may lead to an increase in maintenance costs by using more chemical fertilizers. A careful and economic use of fertilizers and other inputs becomes increasingly important with regard to increasing serious environmental problems. Improving efciency of nutrients can reduce these environmental concerns and economic losses and have benecial effects on plant growth
41.1 Introduction .......................................................................................................................... 917 41.2 Humic Substances ................................................................................................................. 918 41.3 Mycorrhizal Inoculation ....................................................................................................... 918 41.4 Mode of Action of Humic Substances and Mycorrhizal Inoculation ................................... 919
41.4.1 Nutrient Uptake ........................................................................................................ 919 41.4.2 Plant Growth, Root Development, and Architecture ................................................ 921 41.4.3 Plant Quality .............................................................................................................923 41.4.4 Stress Alleviation ......................................................................................................923 41.4.5 Other Benecial and Physiological Effects ..............................................................925
