A computational method to assist evaluation of root length of soybean based on digital image processing

Abstract

The evaluation of the root system is important for better understanding the effects of nutrient management on soil and plant nutri-tion. However, root system studies and culture are slow and show low accuracy. In this context, digital image processing may be an alternative. The objective of this research was to develop a computational method to assist evaluation of the soybean root growth. Initially, the free and open access software, available at: http://rm.deinfo.uepg.br/, was developed in Java platform with the OpenCV library supply through the plug-in JavaCV. To evaluate the software, copper wires with 10 mm, 20 mm, and 50 mm of length manually measured using callipers. They were scanned with a resolution of 300 dpi and then images were loaded in the software. Variation coefficients between 0.01 and 2.99 % were obtained. Subsequently, the samples of soybean roots were scanned and the results of developed software and Safira software were correlated with those from the line-intersect method. The determination coefficients (R² = 0.999) of the developed software, on average, were better than those obtained with Safira software (R² = 0.733), when compar-ing with the line-intersect method. Therefore, the proposed method was accurate for length measurements of soybean roots.