EFFECTIVENESS OF MYCORRHIZAL INOCULANTS ON SEEDED CREEPING BENTGRASS ESTABLISHMENT

摘要

Arbuscular-mycorrhizal fungi (AMF) offer numerous benefits to host plants including improvedresistance to abiotic and biotic stresses. Although the majority of grasses in undisturbed naturalenvironments form AMF relationships, less is known about mycorrhization of turfgrass speciesin maintained situations. The objective of this research was to determine the effectiveness ofmycorrhizal inoculation on establishment of 'Dominant' creeping bentgrass (Agrostis palustrisHuds.). A 38-d greenhouse study was conducted in which pure spores of the mycorrhizal fungusGlomus intmradices Schenck & Smith were added as a soil drench at the time of seeding andfertilizing (Myc-T_0) and 13d subsequent (Myc-T_2). A seeding only treatment (S) and a seedingand fertilizing treatment (SF) served as controls. In addition, a 19-mo field study was conductedby incorporating the commercial mycorrhizal inoculum, endoROOTS~(TM) into 1.52- x 5.79-mplots located on a newly constructed sand putting green prior to creeping bentgrass seeding.Plots not treated with endoROOTSserved as a control treatment. Results from both studiesshowed that creeping bentgrass inoculated with AMF established more rapidly than the controltreatments in terms of producing significantly greater percent endomycorrhizal colonization,percent plant cover, and root weight density (RWD). In the greenhouse study, the Myc-T_0 treat-ment resulted in 50% plant cover 13 d following seeding and fertilizing and 93% after 22 d,compared to 21% and 67%, respectively, for the SF control treatment. In the field study, theendoROOTStreatment resulted in 59% plant cover 16 d following seeding and 95% after 35d, compared to 26% and 68%, respectively, for the control treatment. Results of the field studyalso showed that the endoROOTStreatment produced significantly greater dry clipping weightthan the control treatment during the initial mowing (9.6 and 4.9 g m~(-2) per 33 d, respectively).Although there was no significant difference in RWD between greenhouse treatments Myc-T_0and Myc-T_2, sampled at the 5.0- to 12.0-cm root-zone depth, 38 d following seeding and fertiliz-ing, both treatments resulted in significantly greater RWD than the S control treatment, and theMyc-T_2 treatment resulted in significantly greater RWD than the SF control treatment. In thefield study, the endoROOTStreatment resulted in significantly greater RWD than the controltreatment in the 0- to 7.6-cm root-zone depth on three of nine measurement dates. Results of anoverall analysis of variance for this root-zone depth showed significant treatment (P = 0.013)and date (P = 0.001) effects while the treatment x date interaction was not significant. Also, theoverall RWD mean resulting from the endoROOTS~(TM) treatment was significantly greater thanfor the control treatment (1.36 and 1.14 kg m~(-3), respectively). Hastened establishment ofturfgrasses grown in mycorrhizal-inoculated soils may play an important role in facilitatingearly play and stress resistance on golf courses. Results also indicate that G. intmradices, nowavailable from a variety of commercial sources, is an important component of an effectivemycorrhizal inoculum for golf course turfgrasses.