Primena testa pritiska za merenje sile otvaranja ljuski uljane repice

Abstract

Ripening of oilseed rape crops leads to seed losses due to pod shatter (silique dehiscence) before harvest (natural shedding and climatic conditions) and due to stem shaking during harvest through the operation of combine harvester parts. The vast research interest in solving the pod shattering problem in oilseed rape has been manifested through a body of literature reporting data on several methods developed to measure the pod fracture force. Among the different mechanical methods used to measure the force needed for pod shattering, the pressure test provides the highest level of simplicity. However, devices that measure the mechanical properties of fruits and seeds of agricultural crops are rather expensive, yet highly precise. It is for this reason that a simple and much cheaper device has been designed to measure pod shattering and breaking forces in oilseed rape. The device was used in this study which aimed at determining maximum shattering breaking and detachment forces using the data measurement and aquisition system. Pods of oilseed rape cv. 'Banaćanka' were used in the research. The maximum detachment force in the pod growth direction ranged from 1.25 to 5.14 N. The force needed to break off i.e. detach the pod in the direction opposite to that of its growth was lower i.e. within the range of 0.98-2.98 N. The pod shattering force was measured in two horizontal positions. In the first position, the force was applied in the pod thickness direction, and it was 3.97 N. In the second i.e. lateral position, the vertical force applied to the lateral axis in the pod width direction was 5.08 N on average. The force needed to detach and break the pod off at the pedicel is dependent upon cultivar, moisture, position, size and shape of the pod, pedicel thickness and number of tissues per pedicel. When force is applied along the longitudinal axis, in the pod length direction, the shattering force is 2.16 N. The force required for pod opening depended upon moisture, suture length, pod shape and thickness, number of seeds and morphological traits of the cultivar.