Introduction of Principle of SPAD-502 Chlorophyll Content Tester

Introduction of Principle of SPAD-502 Chlorophyll Content Tester

Spad value refers to the relative content of chlorophyll or “greenness degree”. By knowing the spad value, we can understand the true nitro requirement of the plant, and at the same time, we can also judge the amount of nitrogen fertilizer. Chlorophyll is the main substance that absorbs light, and the padding value is related to the chlorophyll content of the plant. That is, if we can determine the chlorophyll content in the plant, we can know the padd value, which is proportional to the nitrogen content in the leaf. . In this way, we can infer the nitrogen content of the plant, and then guide whether the plant needs to apply fertilizer.

Different wavelengths of light, the absorption of the leaves is different, we can determine the relative amount of the current chlorophyll of the leaf through the two wavelength optical density difference mode 650nm and 940nm (transmission coefficient in the two wavelength ranges to determine the current chlorophyll of the leaf Relative quantity). Using this principle, the SPAD-502 Chlorophyll Content Analyzer was born. The SPAD-502Plus measures the relative amount of chlorophyll in the current leaf by measuring the absorption of leaves in two wavelength bands. The figure below shows the absorbance of the spectrum of chlorophyll in the two leaf samples.