A modern, environmentally safer lime-requirement buffer that replaced the toxic SMP buffer at many labs — and the basis for several states' current lime tables.
The original SMP buffer worked well but contained para-nitrophenol and chromate, which made it hazardous to handle and dispose of. The Sikora buffer reproduces SMP's results without the toxic reagents, so a wave of land-grant labs adopted it.
Like any buffer, it produces a buffer-pH value that the lab reads against its own calibration table to set your lime rate. States including Iowa, Kansas, Kentucky and Minnesota build their lime recommendations on Sikora-buffer calibrations.
Related: Buffer pH · Adams-Evans buffer