Sand pH Effects On Growth and Mycorrhizal Colonization of Velvet and Creeping Bentgrasses.

Velvet bentgrass (Agrostis canina L.) may require less intensive inputs than creeping bentgrass (A. stolonifera L.) for golf course turf but insufficient information is known about the effects of soil pH on its growth. Mycorrhizae may assist plant growth but little is known about soil pH effects on their ability to colonize turfgrasses.  Our objective was to test the effect of pH on growth and colonization by mycorrhizal fungi on velvet and creeping bentgrass.  PVC tubes were filled with a 80:20 sand:peat mixture amended with lime to achieve pH values of approximately 5, 6.5, and 8.  Mycorrhizal fungal spores were mixed into the top surface of the growing medium along with velvet or creeping bentgrass seeds.  Turf was grown in a greenhouse, fertilized weekly with modified Hoagland’s solution, and irrigated three times weekly.  The experimental design was a strip-split plot using five replications, with grass type and pH as strips then split for mycorrhizal fungal inoculum (with and without).  Turf cover data and clipping yield were assessed weekly.  Photosynthesis was measured monthly.  Root samples were collected monthly and examined for fungal colonization.