Determining the Zn content of cherry in field using VNIR spectroscopy.

Visible and near-infrared (VNIR) spectroscopy is an eco-friendly method used for estimating plant nutrient deficiencies. The aim of this study was to investigate the possibility of using VNIR method for estimating Zn content in cherry orchard leaves under field conditions. The study was conducted in 3 different locations in Isparta region of Turkey. Fifteen cherry orchards containing normal and Zn deficient plants were chosen, and 60 leaf samples were collected from each location. The reflectance spectra of the leaves were measured with an ASD FieldSpec HandHeld spectroradiometer and a plant probe. The Zn contents of leaf samples were predicted through laboratory analysis. The spectral reflectance measurements were used to estimate the Zn levels using stepwise multiple linear regression analysis method. Prediction models were created using the highest coefficient of determination value. The results show that Zn content of cherry trees can be estimated using the VNIR spectroscopic method (87.5<r2<96.79). Moreover, plant nutrient contents can be estimated without using chemicals. However, further research is necessary to develop a standard method for field conditions. Because spectral reflectance is affected by ecological conditions, agricultural applications and nutrient interactions, more effective models must be developed depending on the geographical location, period and plant type.