Abstract: When evaluating the comprehensive effect of processing time and electric field intensity on crops, the core issue of how to determine the index weights has confounded the comprehensive evaluation of biological information. It is difficult to determine the equivalence of 1 mg·L^–1 chlorophyll to centimeters of root length. As well, comprehensive evaluation by a weighting sum method may lose some information. Therefore, to determine the comprehensive effects of the electric field condition on crops, we use the basic idea of data envelopment analysis to propose a non-parametric comprehensive analysis method and a corresponding mathematical model for evaluating the comprehensive effects of processing time and electric field intensity on crop growth. This method can overcome above shortcomings and provides an effective tool to analyze the degree of influence of external conditions on biological effects. Finally, we use this method to analyze the comprehensive effects of different electric field intensity and processing time on seedling height and root length of wheat. Different electric field strength and processing time has variable influence on seedling growth, and the change in indexes of biological effects is vibration with increasing electric field from 0.5 to 6.0 kV·cm^–1. With processing time of 5 min, the best processing condition is field strength 1.0 and 2.0 kV·cm^–1. With processing time 10 min, the best processing condition is field strength 2.5 kV·cm^–1.

Key words: comprehensive evaluation, data envelopment analysis, electric field