INSTYTUT DENDROLOGII

Abstract: Fine nonwoody roots (<2 mm) of plants, which are responsible for most mineral and water absorption, are located in the upper 20 to 30 cm of soil. The rhizosphere, the zone around these fine roots, supports diverse microorganisms in great numbers. Dynamic rhizosphere processes involve microbial saprophytic, pathogenic, and symbiotic associations with plants. Certain species of saprophytic bacteria oxidize mineral elements, like P, into soluble forms, fix atmospheric N, stimulate root growth by producing plant growth regulators, act as biological deterrents to root-disease causing organisms, and decompose man-made and natural organic chemicals in the rooting zone. The major symbiotic associations on plant roots are mycorrhizae. There is considerable published research in the world literature proving the biological, physiological and ecological significance of ectomycorrhizae and vesicular-arbuscular mycorrhizae (VAM) to the survival, growth, development and health of many species of agricultural and horticultural plants, and of forest trees. This information is critical to our understanding of plant growth and development and their ecology. In the past, the limiting factors in the practical management of mycorrhizal fungi in plant production have been the availability of affordable and good quality inocula of the ectomycorrhizal and VAM fungi and the development of simple methods to apply these inocula either to the soil or to the roots of plants. It was only after these protocols were developed that scientists could then test under "real-world" conditions the practical and economic significance of the management of these fungi in plant productivity. Many of the problems associated with commercial inoculum production have been eliminated allowing the production of quality products containing ectomycorrhizal and/or VAM fungal propagules to diverse plant markets. These fungal products are being commercially applied to plants in diverse green markets. The results of their application are improved survival, growth and productivity of forest trees and other woody plants on reforestation, urban and reclamation sites, horticultural crops such as those grown in woody ornamental nurseries and various agricultural crops grown in fumigated soils. This presentation is a brief review of the research and operational applications done in support of the practical use of the mycorrhizal fungal technologies in forestry, reclamation, horticulture and agriculture.

Additional key words: Ectomycorrhizae, VAM, practical treatment