Golfdom, April 2013

respect to the number of variations on the concept and probably the gallons produced Alkaline SWEs are the compounds used exclusively so far in my research trials Theyre the filtered mixtures of suspensions of the soluble and insoluble parts of the kelp Heat is typically part of the process and the temperatures used vary with the processor Some processors use temperatures well above the boiling point of water The end product of an alkaline extraction is often dehydrated to a black powder or flaked product to be remixed with water Processors planning to produce a powder aim to chemically and mechanically digest the kelp to maxi mize the yield of the soluble and suspendable solids Settling out of the suspended solids in these products is sometimes a problem DOES RATE MATTER Its a valid question since we are dealing with hormones compounds that cause plant growth changes at very low concentrations nanograms or 10 9 in plant tissues If these compounds are over applied will we see abnormal or injurious growth responses Or since it only takes nano changes in concentrations to have positive growth effects can standard spray rates be reduced The cytokinin levels in the undiluted SWEs that we tested have ranged from 5 to 125 parts per million ppm or 10 6 At normal dilution rates we have compared two SWE sources applied at 35 ppm each or what amounted to about 3 to 4 oz SWE per 1000 ft2 Under heat stress we compared this 1x rate 3 oz to 01x and 10x rates for effects on creeping bentgrass Our results showed that rate mattered in terms of applying enough The 01x rate did not supply enough cytokinins to match the improvements seen with turf quality chlorophyll levels and nitrate uptake provided by the 1x rate However these positive heat stress tolerance effects were matched by the 10x rate with no negative consequences The 10x rate did not provide any measures of improved stress Super Science 38 Golfdom April 2013 Golfdom com PHOTO BY NICK SEAVER A nodosum on the coast of Maine Continued from page 37 Cytokinin levels must remain elevated in leaf tissues to slow the summer decline process As summer root decline proceeds leaf tissue cytokinin levels drop