One-year extension of a project started in 2016 to evaluate Melspring/Olmix’ sand/soil improvers Stor-it and Matrix, both containing natural zeolite and Matrix also containing seaweed. The amendments were mixed at 10% (v/v) ratio into the top 5 cm on a USGA-spec. green with an initial organic matter content of 0.8% (Sphagnum peat) before sowing creeping bentgrass on 9 June 2016. Stor-it and Matrix increased the pH and cation exchange capacity of the substrate and accelerated bentgrass establishment significantly compared with the unamended control. The fastest grow-in was achieved with Matrix, which, unlike Stor-it, contained 1.1% N and increased the water-holding capacity of the upper rootzone.
After grow-in was completed, Stor-it and Matrix continued to be added in the monthly topdress. Plots were split into four subplots with Melspring’s organomineral fertiliser Marathon or the readily available liquid mineral fertiliser Wallco (control, 2-wk interval, but same total N rate) under two irrigation regimes. During this period, both Stor-it and Matrix resulted in firmer greens, while overall turf quality was improved by Matrix, but reduced by Stor-it, compared with the unamended control. Matrix also incurred two disadvantages: reduced root depth and more microdochium patch. The effects of Marathon vs. Wallco fertiliser were mostly insignificant except that Marathon gave lower N concentration in turfgrass clippings in both 2016 and 2017, suggesting that this fertiliser needed more time to trigger a microflora conductive to mineralisation.
In phase II of the project, starting 1 May 2018, the protocol was modified to optimise use of Stor-it, Matrix and Marathon under Nordic climate conditions. Marathon TCR (Turf Core Renovator) was introduced as an alternative to topdressing with Matrix during the first part of the season (until 1 August), after which Stor-it was used in all treatments to lower the soil water content and enhance rooting before winter. Furthermore, application of Marathon was discontinued in mid-September, one month before Wallco, to avoid microdochium patch in late autumn and winter. These changes clearly improved the performance of the Melspring/Olmix products in 2018. In particular, the combination of Marathon and Marathon TCR improved turfgrass recovery after a tough winter and alleviated the potentially negative effect of autumn-applied Stor-it on turfgrass quality in spring.
