Abstract
Continuous and nondestructive measurement of plant growth in weight is considered to be one of the fundamental techniques used in studying mutual relations between plant growth and its environment. From these standpoints, this study directs to developing measurement systems of plant growth.
A cantilever beam was made by an elastic thin metal plate and a holder of plant stem is attached on its free end. Four strain gages were adhered to different cross sectional parts a distance apart on this beam and composed a bridge circuit. By this circuit, difference of bending moments caused on the beam by plant weight was converted into output voltage and measured. Detection of moment difference has a merit that it is not affected by a change of the acting position of loads. Therefore, it is possible to measure pure plant weight separately no matter how posture of plant changes. Using these weight beam sensors, total measurement systems have been developed and some experiments of cultivating plants in simple and community state have been made. These experimental results can be considered to have enough possibilities for measuring plant growth weight.
