Effect of irrigation, fertiliser type and soil amandment on turf quality and organic matter accumulation/thatch control on creeping bentgrass greens

Summary

This project is comparing Melspring’s sand/soil improvers Matrix and Stor-it (containing natural zeolite) and Matrix (also containing seaweed) with an unamended control. In 2016, Matrix or Stor-it was mixed at 10% (v/v) into the top 5 cm of a USGA-spec. green with initial organic matter content 0.8% under a mobile rainout shelter at NIBIO Landvik. The green was sown with creeping bentgrass on 9 June 2016. Applications of Matrix and Stor-it continued as part of topdressing. Once grow-in was completed on 5 August 2016, two more experimental factors were added: 1) During four weeks in 2016 and eight weeks in 2017, the rainout shelter was activated and main plots either irrigated to field capacity (FC) once a week or excess-irrigated twice a week with 50% more water than needed to replenish FC; and 2) Marathon controlled-release fertiliser applied every 4 weeks was compared with Wallco liquid mineral fertiliser applied every 2 weeks. Total N rate during the maintenance period was 10 and 18 g N/m² in 2016 and 2017, resp.. Due to its seaweed content, Matrix added a further 33 g N/m² before sowing, and 2.3 and 4.1 g N/m² in topdressing in 2017 and 2018, resp. This extra N was not compensated for on unamended or Stor-it plots.

Major findings from 2017 are:

• Matrix increased soil water-holding capacity (SWC) at both 0-38 mm and 0-200 mm. Stor-it decreased SWC at 0-38 mm, but gave the same SWC at 0-200 mm as the control
• Matrix resulted in more Microdochium nivale and thus reduced turfgrass quality in spring, but recovery from nivale was fast, resulting in better quality during and after the irrigation period in summer/autumn
• Stor-it resulted in lower turf quality than the control throughout the year. It seems to be more effective in wet conditions
• Both Matrix and Stor-it gave shorter roots but harder playing surfaces than the control.
• Marathon gave equal/ better turf colour than Wallco from spring to the first part of the shelter period in June. Wallco produced better turf quality than Marathon during the latter part of the shelter period in July and the two following months. However, despite more the annual N being given in autumn in the Wallco than the Marathon treatment, turfgrass colour was better with Marathon than with Wallco by late October. This may be an effect of higher mineralisation of organic matter.

Study commissioned by Melspring BV, STERF industrial partner. Final report will be made when chemical analyses are completed (Feb. 2018).

Fundings (kSEK)