SCANNING THE TURFGRASS RESEARCH JOURNALS

By Dr. John Cisar Overview Dr. John Cisar

With an eye to locating gems of research that can have an impact on our sod production industry, with this issue, we begin a feature for our members that summarizes results from recent published works by turfgrass scientists around the world. In typical years, over 60 articles

are published in scientific journals that may or not get disseminated rapidly to end-users. Scientific, peer- reviewed papers form the foundation for advancing our industry through well-designed experimentation. We will attempt to speed up the process of getting information out to you, the interested industry, with these brief highlighted snapshots on published research by providing our readers with up-to-date reporting of current trends in research from all regions.

Although a small percentage of scientific papers focus directly on aspects of sod production, much of the literature out there will have information that is very relevant to production, management and environmental protection for sod producers. I believe that this information will not only make sod producers more aware of what is happening at our research institutions but also encourage increased engagement between the industry and turf research and bring about even more studies on sod production.

I hope you find this article enjoyable and enlightening. In this issue, I focus on three sod production research studies conducted on cool-season turfgrass sod in the USA and reported in the scientific literature in 2016.

Our first summary from 2016 is on sod research conducted at the University of Wisconsin from 2009-2013. Using sod or crop production has been a popular avenue for disposing waste products over the years. In this study the authors investigated locally-generated materials for suitability in growing acceptable quality sod.

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TITLE: Biosolids as an alternative fertilizer for Kentucky bluegrass sod production in Wisconsin.

Authors: Shane Griffith, Nicholas Bero, John Stier, Glen Obear, Sabrina Ruis and Douglas Soldat.

Journal: Crop Science, 2016.

Tis multi-year field study with several harvests focused on determining the agronomic impacts of using two sources of biosolids as Nitrogen (N) fertilizer sources compared to conventional practices on sod production evaluating turf quality and sod tensile strength as main criteria.

Te biosolid treatments were anaerobically-digested biosolids cake or biosolid cake mixed with sand and sawdust at a 2:1:1 ratio by volume (Metro-Mix®). Te biosolids were applied at three rates based on their supply of plant available nitrogen at 250, 500, and 1000 kg N/ ha (approximately 5, 10, and 20 lbs. N/1000 sf) for the biosolid and 250, 375, and 500 kg N/ha (approximately 5, 7.5, and 10 lbs. N/1000 sf) for the Metro-Mix. Applications were made in each of three years after harvest to gauge the effect of continued N release from organic materials. Te lowest biosolids rates mimicked the maximum annual N rate for growing Kentucky bluegrass sod. Te conventional sod production fertilizer treatment was applied at 309 kg N/ha/per harvest cycle (approximately 6 lbs. N per 1000 sf at about 1.5 lbs. N/1000 sf per application over a 20-month cycle) and supplemented with P and K to mimic those nutrients found in the biosolid treatments. Please note that sod production N is limited to 280 kg/ha/year (5.7 lbs/1000 sf) so the overall application did not exceed yearly thresholds, but some biosolid rates did in the research study. Te trial site soil was a silt loam.

Among the key findings, the authors concluded from optimization modeling that biosolid cake applied at the rate of 425 kg N/ha (approximately 8.7 lbs N/1000 sf) in the first year would likely meet color, quality and tensile strength of conventionally-fertilized sod at routine harvest frequencies. Nitrogen source did not affect production cycle length during the study. Moreover, less biosolid cake (at rates of 325 and 285kg N/ha/production cycle or 6.6 and 5.7 lbs N/1000 sf, respectively) would be required for subsequent (second and third) production cycles

TPI Turf News January/February 2017