Vol. 85, No. 1
Abstract
Review about Requirements for Access Road Strength
──Strength Requirements for Climbing Access Road─
[Keywords: access road, strength, slope angle, pulling force, tractive coefficient, slip rate, trafficability, cone index, soil hardness]
Detection of Salinity Stress of Soybean Utilizing the Laser Speckle Method
[Keywords: laser speckle, salinity stress, drought stress, chloroplast, image processing]
The global agricultural area has been decreasing due to salinity levels in the soil. Salinity stress is difficult to detect in plants, because the initial symptoms are similar to those of drought stress. Salinity stress has been reported to change the movement and morphology of chloroplasts; therefore, we inves- tigated the applicability of using a laser speckle that can evaluate chloroplast movements to detect stress levels of soybean. Comparisons between salinity and drought treatments revealed that the speckle feature could reflect the differences in the type of stress. In addition, the feature clearly changed compared to that of SPAD and leaf temperature that were used as indicators of plant physio- logical information. Thus, laser speckle can be effective for detecting salinity stress.