The Effect of Mycorrhizae Products On Nutritional Status of Marigold, Tagetes Patula

Marigold (Tagetes patula) seedlings were evaluated for their response to two commercially available mycorrhizae products, Mycormax and Mighty Myco. These are two of the numerous products containing a blend of mycorrhizae species available to commercial growers and the general market. Claims for these products suggest that they can increase absorption and translocation of essential plant nutrients including phosphorus, sulfur, calcium, zinc, and copper. The purpose of this research was to discover whether commercially available mycorrhizae products could increase nutrient uptake in a common bedding plant, thus reducing fertilizer requirements. Phosphorus is used to a great extent in the production of bedding plants, and is a major contributor to water quality problems, leading to an overabundance of algae and eutrophication when present in excess amounts. Marigolds were evaluated for germination rate, time to first visible flower bud, time to first open flower, and nutrient status at harvest. Slight differences were seen in germination rate, flower buds, and open flowers. Foliar analysis indicated that marigolds grown with Mycormax had higher levels of nitrogen, phosphorus, potassium, magnesium, calcium, and manganese; slightly higher levels of sulfur, boron, and copper than either Mighty Myco or the control treatment. Mighty Myco had slightly higher levels of zinc than Mycormax, and much higher levels of iron, while the control treatment had far higher levels of iron than either mycorrhizae product. Whereas the increase in phosphorus in the Mycormax treatment was not large (0.33% as compared to 0.25% for Mighty Myco, and 0.27 for the control), nitrogen level differences were more notable (1.66% for Mycormax compared to 1.08% for Mighty Myco and 1.12% for the control). The results of this research indicate that it may be possible to reduce fertilizer use in production of bedding plants, but further studies are required to confirm these results.