EN
This is an important issue for the evaluation of behaviour of the wheat mass during the harvest. A stem developes natural asymmetries, which determine the character of its movement during the interaction with the pickup reel and knife. The dynamics of the bending line recorded on a film allows for assessing, provided the exciting force is known, the material constants of the plant after its geometry has been determined, i.e. ∆z and ∆G. Apparently, the problem is solvable only in the case of very simple constitutive models. The most important result obtained within the present study is the confirmation of thehypothesis of pronounced polarity of the medium.