The application of spectral properties as a diagnostic tool in nutrient deficiency diagnosis requires further understanding of the relationship between spectral properties and nutrient concentration in plant tissue.Therefore

to examine the effect of variable potassium fertilization on corn（Zea mays L.） leaves and the response on leaf spectral reflectance.We designed an experiment to examine the effect variable amounts of potassium fertilization during four stages of corn growth.Our results showed that the difference in potassium leaf content is significant at the 0.05 probability level with increasing potassium fertilization.We then examined the correlation between corn leaves spectra reflectance and nutrient content as a function of variable levels of potassium fertilization over the entire corn growing season by potted plant experiment.Digital models were constructed to assess potassium content in leaves by utilizing leaves spectral reflectance in the booting stage Our results showed that there was a correlation between the spectral reflectance of corn leaves and corresponding leaf inner moisture

chlorophyll and other nutrient content including nitrogen

phosphorous

potassium

calcium

magnesium

copper

iron

manganese

and zinc.These differences in the spectral reflectance held for the entire growing season.730—930 nm and 960—1100 nm were defined as sensitive wave bands to assess potassium nutrition condition in booting stage

and spectral variables including R767+R1057

（R767+R1057）/（logR767+logR1057） and（R767-R1057）/（logR767-logR1057） could predict accurately corn leaf potassium-content in the booting stage.Our analysis indicated a correlation between various components in the inner leaves and spectral reflectance at this stage.Inflection points occurred at 410nm

550nm

710nm

950nm in every curve.When correlations between the various components were high

their spectra correlation curves were coincident or symmetrical.