P. AHMADI MOGHADDAM - Urmia University

ABSTRACT- The evaluation of leaf area and leaf nutritional value is important for crop growth modeling and estimations of its performance. The purpose of this study was to use image processing techniques to develop an economical method to ease the assessment of nutrient status and leaf area (LA) of plants and to compare the outcomes of this method with linear models. Leaf area and leaf chlorophyll (LChl) estimation models were developed for apples (Red delicious and Golden delicious) using a leaf area meter and a chlorophyll meter (SPAD ۵۰۲), respectively. Linear models were developed by measuring the length (L) and width (W) of the leaves. Two models (LA= ۱.۰۱ + ۰.۸۲LW and LA= ۱.۲۳ + ۰.۸۷LW) were found to provide the most accurate estimations (R ۲ = ۰.۹۴, MSE = ۴.۶ and R ۲ = ۰.۹۴, MSE = ۴.۷) of leaf area for Red Delicious and Golden Delicious apples, respectively. Results also showed that the image processing technique was able to estimate leaf area with good accuracy (R ۲ = ۰.۹۸, MSE = ۴.۶). The calculation of leaf  area in this technique is easier and more accurate than linear models. The best model for leaf chlorophyll estimation using the image processing technique was (LChl= - ۰.۵۵ red - ۰.۴۵green +۰.۳۲ blue + ۹۲) which was highly accurate (R ۲ = ۰.۹۵, MSE = ۷.۴).

Keywords: Apple, Image processing, Leaf area, Leaf chlorophyll, Linear measurement