Non-destructive Measurement of Fresh Plant Mass by the Gamma-scanning Technique Applied to Broccoli

In horticulture, agriculture and forestry, scientists often face the task of determining the fresh matter of plants. In the classical approach, this is undertaken by harvesting and weighing. This method not only requires a large area, a high number of plants and expensive labour investment, but also sacrifices the plants. By using the gamma-absorption technique combined with a scanning device, crop mass and growth can be measured continuously and non-destructively in the field. The measuring procedure and the structure of the device are described herein. The accuracy of mass determination depending on growth stage was examined by weighing the broccoli plants (Brassica oleracea L. convar. Botrytis var. Italica Plenck, cv. Emperor). The plant mass measured using gamma absorption was in agreement with the mass obtained from weighing. The results were within a coefficient of variation of lower than 4% beginning at the sixleaf growth stage, and lower than 2% beginning at the nine-leaf growth stage. The utilization of non-destructive measurements, which could be taken continuously in small time intervals on the same canopies, made it possible to assess the reaction of plants and their dependence on environmental factors by growth analysis.