Mycorrhizal diversity is important

Mike Amaranthus PhD

Mycorrhizal Applications Inc

Natural areas generally contain an array of mycorrhizal fungal species. The proportions and abundance of mycorrhizal species often declines following any disturbance. Not all mycorrhizal fungi have the same capacities and tolerances. Some are better at imparting drought resistance, others are more important in protecting against pathogens, still others are more tolerance to soil temperature extremes. Because of the wide variety of soil, climatic, and biotic conditions characterizing man-made environments, it is improbable that a single mycorrhizal fungus could benefit all host species and adapt to all conditions. For example, the types and activities of mycorrhizal fungi associated with herbaceous plants are often different than those associated with woody plants. Mycorrhizal fungi have differing abilities to produce antibiotics that retard soil pathogens. Likewise, some mycorrhizal fungi are better at producing enzymes that facilitate mineral uptake such as phosphorous and iron. Still other mycorrhizal fungi can access organic forms of nitrogen. Mycorrhizal diversity likely provides a range of benefits to the plant not found with only one species. The diversity of mycorrhizal fungi formed by a given plant increase its ability to occupy diverse belowground niches and survive a range of chemical, biological and physical conditions.

The mycorrhiza products we produce contain the most diverse and effective strains of mycorrhiza available anywhere. By utilizing this robust mix of beneficial soil organisms, plants can survive and thrive the way nature intended. The following discussion summarizes the particular characteristics and benefits of some of the major species used in our mixes.

Glomus mosseae

Glomus mosseae is one of the most researched endomycorrhizal fungi. Numerous studies have determined the importance of G. mosseae in:

• Nitrogen and phosphorous uptake
• Enzyme activity to access micro nutrients
• Nematode control
• Root stimulation
• Improved performance of woody perennials
• Control of pathogenic fungi

Glomus aggregatum

Studies have determined the importance of the endomycorrhizal fungus G. aggregaturn in:

• Improved plant performance in sandy soils
• Control of root rots
• Effective colonization with time release fertilizers
• Tolerance of high fertility levels
• Improved performance of Palms, Fruit trees.

Glomus intraradices

Glomus intraradices is the most widespread and researched endomycorrhizal fungi. Numerous studies have determined the importance of G. intraradices in:

• Phosphorous uptake
• Nematode control
• Can access organic forms of nitrogen and phosphorous
• Improved growth and performance of turf grasses, agricultural crops and citrus
• Control of fusarium
• Drought protection

Pisolithus

Pisolithus is a ectomycorrhizal genus that is widespread across an array of diverse habitats and host plants. We use a blend of 5 ecotypes in our mycorrhizal formulations which assures rapid mycorrhizal formations across a variety of environmental conditions. Documented benefits include:

• Rapid early growth of inoculated tree species
• Increased short root production
• Tolerant of hot, dry conditions
• Amelioration of heavy metal toxicity
• Inhibits soil pathogen growth and plant infection
• Benefits plants in disturbed environments

Rhizopogon

Rhizopogon spp is a truffle species that has numerous special qualities important in a soil inoculation program. Rhizopogon targets a wide range of ectomycorrhizal tree and shrub species.

Rhizopogon is a large mycorrhizal genus that occurs on both young and old plants, in diverse habitats and are present on every continent but Antarctica. This ecological amplitude was recognized early in the 20th century when Rhizopogon species were observed as dominant ectomycorrhizal fungi in exotic plantings. Rhizopogon occurs naturally across the United States, in Mexico, Japan, China, Europe and North Africa. Numerous factors make Rhizopogon a prime candidate for soil inoculation programs both nationally and internationally. Functional activities that benefit performance include:

• Defends against diseases
• Promotes soil structure
• Tolerant of cold soil temperatures
• Tolerant of a broad pH range
• High levels of enzyme activity benefiting nutrient acquisition
• Can utilize organic forms of nitrogen
• Protects seedlings against moisture stress
• Promotes successful plant establishment and growth

Consequently, Rhizopogon has been the focus of considerable application research. The ease, viability and effectiveness of spore inoculation are well documented. The low-cost nature of spore inoculation and the improved outplanting performance of Rhizopogon inoculated plants is driving increased use of Rhizopogon in practice. Nearly 200 scientific papers have been published on Rhizopogon and this important body of information is now being put to practical use.