Determination of Leaf Area of Some Vegetable PlantsGrown under Greenhouse Condition by Non Destructive Methods

Abstract

The use of a mathematical model approach, which is a non-destructivemethod to determine the leaf area, has been used safely in recent years. Themost important reason for this is that the application is easy and the applicationcost is very low. The most important disadvantage of this method is that thederived models need calibration according to different crop varieties. In thestudy, firstly, the width (W) and length (L) measurements of each individualleaf taken from the crops were correlated with the actual area of the leaf andcrop-specific models were developed. The actual area (LA) of each leaf usedin the sampling was determined by the ImageJ software. In the study, 7different models were derived for each crop species (1,LA=a+$bL^{2}$+$cL^{2}$ /$W^{2}$+$dW^{2}$+eLW; 2, LA=a+$bL^{2}$+$cW^{2}$+dLW; 3, LA=a+$bL^{2}$+$cW^{2}$ ; 4,LA=$aL^{2}$+$bW^^{2}$ ; 5, LA=aLb+cWd+e; 6, LA=a+bLW; 7, LA=aLW). The coefficientsin the models were determined separately for each crop species. In order toevaluate the performance of the models, some performance criteria such asdetermination coefficient ($R^2$) ) and root mean square error (RMSE), relativeerror (RE), mean bias error (MBE) and Willmott index (d) were used. In thisstudy, leaf areas were estimated with high accuracy ($R^2$=0.96 for tomato;$R^2$=0.99 for pepper, eggplant and cucumber) with these models without usingexpensive measuring devices.