Agriculture/Horticulture Information

Mycorrhizae and Fertilizer

Mycorrhizae have been observed in fossils dating back 400 million years to about the time that higher plants began the gradual move from aquatic to terrestrial environments. Many scientists believe that the diverse range of plant species would have never occurred if it were not for Mycorrhizae. This fungus is wholly dependent upon relationships with higher plants and attaches itself to roots in order to obtain carbohydrates which the plant provides. In exchange, mycorrhizae perform a myriad of chores to protect the plant and encourage growth. Most importantly, it grows a complex network of fungal filament that can mine a far greater area of the soil based moisture and nutrients than a naked root. (up to 50 times more area). It also produces a complex by product known as "glomalin" that improves soil structure allowing greater movement of moisture the topsoil and into natural aquifers.

Ground Water Pollution

Conventional agriculture is dependent upon chemical fertilizers as a source of plant food. Application rates must be significantly higher when "mycorrhizae" and other beneficial organisms are not present to extend to grasp of plant roots into a far greater volume of soil. The results are that fertilizer applied but not used by the crop can leach into the ground water.

Water Management

Water use in the county has become a serious concern to the entire population both in and out of the agricultural community. Fields that were flood irrigated only a few years ago are now on drip systems. Without mycorrhizae, the beautiful oaks and chaparral that grace our hills would not be there. The deserts of the south and the Great Basin that come to bloom each spring would be dustbowls without the symbiotic relationship between plants and fungi. Perennial crops such as grapes can grow and thrive with much less water when mycorrhizae is abundant.

And Speaking of Grapes

The French call it "Terrior"; that mysterious quality given to a wine by the influence of the vineyard’s soil. Grapes are highly dependent upon mycorrhizal association and when the vines are not well colonized by the fungi, they are not able to procure a balanced and appropriate level of plant micronutrients such as zinc, copper and sulfur that have a dramatic influence on the character of the fruit.

Chemical Free Lawns.

Golf courses, Sports fields and Residential lawns tend to be overwatered, over fertilizered and over sprayed with pesticides in order to give them an appearance of healthy lush growth. In reality though, the excessive use of water, fertilizer and pesticides weakens the root systems and makes turf more prone to disease problems. Over watering combined with foot or vehicle traffic leads to soil compaction, making it difficult for water to drain and roots to grow. Over fertilization produces "luxurious comsumption" that creates greater vulnerability to diseases. Pesticides, particularly fungicides will kill mycorrhizae and other beneficial soil organisms that are part of the plants immune system. Mycorrhizae, on the other hand can reduce water demands by the turf and it can also improve the soil structure, combating soil compaction. Fertilizer needs are far less because of the greater nutrient use efficiency associated with a strong mycorrhizal connection and attacks by root diseases are less likely because of the improved immune system.

Watch Phosphorus

Fertilization Phosphorus plays a major role in the establishment and functioning of the symbiosis. High phosphorus fertilization limits mycorrhiza effectiveness, but low to moderate levels of phosphorus or the use of slow release forms such as rock phosphate maximize plant benefits from mycorrhiza.

Limit Use of Fungicides

Some fungicides have been found to damage AM fungi.

Limit Soil Disturbance

Severe disruption of the soil hyphae limits nutrient and water movement into the plant root.

Match AM fungi with Host and Soil

While AM fungi are not host-specific, there are some associations that are more effective than others in benefiting the plant. AM fungi also differ in their tolerance of different soil factors. Therefore it will be a future priority to match AM fungi with host and soil in order to optimize the use of inoculum and maximize the plant benefit. Care must be taken in order to maximize plant benefit to inoculation. AM inoculum is like no other soil amendment. The purpose behind inoculating with AM fungi is to establish a functioning healthy biological symbiosis. A beneficial symbiosis is dependent upon the right balance between the needs of the plant and that of the fungus.

• Increase Plant Establishment
• Sustain Plant Production and Productivity
• Reduce Soil Erosion
• Reduce Transplant Shock
• Reduced Use of Fertilizers and Pesticides
• Lower Water Requirement
• Increased Soil Aeration and Drainage
• Increase Resistance to Invasive Weeds