The invention discloses a dynamic leaching-spectrophotometric detection method for the release rate of nutrients in a slow-release
fertilizer, and relates to the field of
agrochemical analys.The detection method comprises the following steps that S1, a slow-release
fertilizer sample is placed in a leaching column to be leached, and
leachate is collected; s2, sequentially adding a
masking agent solution and a
chromogenic reagent into the
leachate, and carrying out
chromogenic reaction; s3, pumping the solution into a double-optical-path
flow cell, and measuring
absorbance values under a target
nutrient characteristic absorption
wavelength and a background interference characteristic
wavelength; s4, calculating the corrected net
absorbance; and S5, calculating the
nutrient concentration, and drawing a
nutrient release
kinetic curve. By adopting a dual-
wavelength synchronous detection and real-time dynamic subtraction
correction algorithm, the method can eliminate
system errors of time-varying background
chromaticity, so that accurate and reliable
absorbance readings can be obtained at the initial stage of nutrient release even if the nutrient concentration in the
leachate is very low, thereby ensuring the authenticity of the initial stage of a release curve and improving the accuracy of nutrient release. And initial release kinetic parameters are accurately captured.