Working with Nature to Create Vigorous, Healthy Turf
By Thomas D. Landis, Ph.D.
Vigorous, healthy turf requires more than just soil, water and fertilizer. The unique blending of improved selections of turfgrass in Pennington Smart Seed™ with MycoAdvantage™ will produce turf that is not only thick, green and durable, but requires less irrigation and fertilization.
What is the MycoAdvantage?
Most grasses form a mutually beneficial relationship with a unique type
Figure 1 – A network of hyphae from endomycorrhizal fungi (A) extend out from grass roots into the soil, greatly increasing access to water and nutrients. This adsorptive advantage allows grasses to grow more roots and become established faster (B). (In B, 5% confidence intervals were computed using Fishers PSLD test).of soil fungus called a mycorrhiza, which means “fungus-root.” Although there are several mycorrhizal types, endomycorrhiza are found on grass roots and produce fungal hyphae which radiate out to form an extensive fibrous network (Figure 1A). This fungal network provides several benefits to young grass plants but most importantly it increases the root mass and the ability to absorb more water and mineral nutrients. This absorptive network allows young grass plants to grow more quickly and become established much faster than plants without the mycorrhizal advantage. When Smart Seed bermudagrass was inoculated with MycoAdvantage, it grew rapidly and established complete coverage almost twice as fast as the control (Figure 1B).
Mycorrhizal fungi reproduce by spores and, although they occur in natural grasslands, mycorrhizal spores are absent in newly sown seedbeds. One important characteristic of mycorrhizal fungi is that the relatively large spores (Figure 1A) are not distributed by wind but are only introduced by water or soil movement. This means that mycorrhizal spores must be deliberately introduced into new grass sowings which brings us to the “MycoAdvantage” of Pennington Smart Seed.Using an innovative new technology, grass seeds are inoculated with a proprietary blend of mycorrhizal spores which remain dormant until they become wet after sowing. This ensures that grass roots are colonized and mycorrhizae form soon after the seeds germinate which greatly reduces the moisture and nutrient stress that so often retard sod turfgrass establishment.
Turf with the MycoAdvantage Requires Less Water and Fertilizer
To demonstrate how the MycoAdvantage works, a recent research trial was conducted to compare Smart Seed Sun & Shade mix with and without mycorrhizal inoculation. Special pots were filled with a typical mixture of 3 parts sand to 1 part Sphagnum peat which was amended with APEX (23-6-12) controlled release fertilizer. The control pots were seeded with untreated Smart Seed and the treatment pots were sown with MycoAdvantage inoculated Smart Seed. After sowing, both sets of pots were irrigated either of two watering rates: 0.16 to 0.26 gal (0.6 or 1.0 l) per week. Extensive measurements and photographs were taken of the test pots including grass cover establishment, mycorrhizal colonization, grass biomass, foliar nutrient levels, and soil respiration – an indication of root health.
Figure 2 – After one month, Smart Seed Sun & Shade grass with MycoAdvantage was much greener and healthier than the control treatment (A), but the most impressive difference was the more vigorous and extensive roots on the MycoAdvantage plants (B). The increased health and physiological activity of these roots and associated mycorrhizae are verified by soil respiration measurements (C). (In C, bars with different letters are significantly different at a 5% significance level using Fishers PSLD test).Both sets of pots were watered to saturation and, after the young grass plants were established, they were subjected to one week of typical southwestern Oregon temperatures of over 100°F (38°C) and low humidity which produced severe moisture stress. The Smart Seed with MycoAdvantage grass plants grew better and stayed greener than the control plants which demonstrates the beneficial effects of the mycorrhiza treatment even this early in the growing season.
The grass treatments were allowed to grow for another month and the pots without MycoAdvantage showed signs of stress and reduced turfgrass quality. On the other hand, the Smart Seed Sun & Shade grass pots remained a healthy green and there was little difference between the two irrigation treatments (Figure 2A). This increased growth and better color is evidence of the more extensive and functional root system (Figure 2B).
The root mass is not only larger and more expansive, but is more vigorous and healthier. This increased physiological activity can be monitored with a Solvita Kit which measures soil respiration, and is an index of the biological activity of roots and other soil organisms. Solvita measurements showed that the MycoAdvantage increased the respiration of the Smart Seed Sun & Shade grass compared to the control grass (Figure 2C). Even more amazing is that the respiration rates were the same for the two different irrigation treatments proving that grass plants with MycoAdvantage can better tolerate occasional drought stress.
Summary
So, as you can see, inoculating Smart Seed with MycoAdvantage not only grows quality turfgrass faster but will produce vigorous healthy root systems with abundant mycorrhizae that help tolerate water and nutrient stresses. The healthier turfgrass can lead to fewer call backs and happier clients with less total input cost.
Thomas D. “Tom” Landis is with Native Plant Nursery Consulting, Medford, Ore. He can be reached via e-mail at nurseries@aol.com
