Summary
Field and laboratory studies with creeping bentgrass (Agrostis palustris 'Penncross') growth in a sand/peat (4:1) medium recommended for putting greens showed that turf inoculated with the arbuscular mycorrhizal fungus Glomus intraradices was able to tolerate drought conditions significantly longer than non-mycorrhizal turf.
- Mycorrhizal turf recovered more quickly from wilting than did non-mycorrhizal turf.
- Leaf water potentials remained higher in the mycorrhizal turf and declined at a slower rate than in non-mycorrhizal turf.
- Protection against drought was conferred by G. intraradices when turf was grown under conditions of low phosphorus fertilization (11 mg/l), but the benefits disappeared when the P concentration of the fertilizer was quadrupled to 44 mg/l.
- Of eighteen free amino acids and amides studied, y-amino-n-butyric acid was the best indicator of water stress.
- Mycorrhizal turf maintained significantly higher chlorophyll concentrations (avg 29% more) than did non-mycorrhizal turf during the ten-day-long drought in the field.
Why This Research Matters
This study is particularly relevant for turf managers, golf course superintendents, and anyone growing grass in water-constrained conditions. The 29% higher chlorophyll retention during a ten-day drought is a practical measure of how much longer mycorrhizal grass stays green and healthy without irrigation.
The finding that benefits diminish at high phosphorus fertilization levels is also consistent with broader mycorrhizal science: when plants receive abundant nutrients from external inputs, they reduce their investment in the mycorrhizal relationship. This underscores the value of using mycorrhizal inoculants alongside reduced fertilizer programs — both for cost savings and for maximizing the symbiotic benefit.
What This Means for Turf Growers
For golf course superintendents, sports turf managers, and lawn care professionals, water is one of the largest operating costs and regulatory concerns. This study provides quantified evidence that mycorrhizal inoculation at establishment can meaningfully reduce irrigation demand and extend drought tolerance — without chemical inputs.
Practical takeaways from this research:
- Inoculate at seeding or sodding, not after establishment. The benefits are rooted in early colonization of new root tissue.
- Reduce phosphorus during establishment. Keep P applications below 20 mg/l to avoid suppressing colonization. Switch to nitrogen-forward programs once the turf is established.
- Expect greener turf under drought. The 29% chlorophyll advantage translates directly to better color retention during dry spells — a key quality metric for high-visibility turf.
Big Foot Root Boost is formulated specifically for turf applications, combining endomycorrhizal spores with active carrier ingredients that promote rapid colonization in sand-based growing media — the same type used in this study.
Built for turf. Backed by science.
Big Foot Root Boost is formulated for lawns, turf, and grass — with active carriers for fast colonization.
Shop Big Foot Mycorrhizae