Phosphorus saturation index and P deficiency

Jason Haines (@pendersuper on Twitter and the author of the Turf Hacker blog) posted an interesting observation recently. Jason noted that greens were struggling following application of increased nitrogen — instead of increasing growth, greens continued to grow slowly. Jason also noted that following application of a phosphite product as part of his disease suppression program, greens looked even worse. It is known that phosphites can interfere with uptake of phosphate, so Jason suspected a phosphate problem and applied a…