Belowground microbial processes underpin forest productivity.

Abstract

Nitrogen-fixing bacteria associated with mycorrhizal fungi and mycorrhizas can be demonstrated with microaerophilic procedures. The chemical substrates in mycorrhizal fungi or mycorrhizas often stimulate the growth and nitrogenase activity of the associated N₂ fixers. In addition, the associated N₂ fixers are producers of plant-growth-promoting substances and B-group vitamins. Combined inoculation of mycorrhizal fungi with N₂ fixers enhances mycorrhiza formation. Other microbes in the mycorrhizosphere have capacities to breakdown primary minerals, thereby releasing nutrients available for uptake by plants. Thus, land restoration can be achieved by planting trees with nitrogen-fixing and rock weathering capacities, such as alders and some pines. The treatment can enhance nutrient availability and increase soil organic matter that provides organic substrate for nutrient release, maintain soil structure and enhance water-holding capacity. Also changes in tree species compositions on the site are likely to alter belowground processes through changes in functional processes of organisms that constitute ecosystems.

Citation

Li, C.Y.; Strzelczyk, E. 2002. Belowground microbial processes underpin forest productivity. Phyton (Horn, Austria). 40(4): 129-134