The impact of grain combine harvester working parts on damage and quality of winter wheat seeds

The aim of the study was to improve the quality of winter wheat seeds of the Fortuna and Yuvileina varieties by reducing damage during harvesting with a combine harvester at various stages of the technological process. Based on a comprehensive approach and the interrelation of climatic and soil characteristics, theoretical calculations, mathematical models, experimental, production and laboratory studies, the influence of the working parts of drum and rotary grain harvesting threshing units on microtrauma to seeds and its impact on the development of microorganisms and, in turn, on seed quality indicators, which significantly affect crop yield. The mathematical model of a damaged spring-viscous ellipsoidal grain provided by the authors shows that during the impulse force of relative and absolute trajectories of motion and acceleration, Coriolis forces, inertia, friction, and friction, when the rotation speed of the drum or rotor increases, the deformation of grains weighing 0.03-0.06 g with a transverse diameter of 3-5 mm within the range of 600-700 rpm is 0.015-0.035 mm, and damage increases significantly due to a decrease in seed strength, stress and force. Microtrauma at drum speeds of 700 to 1,000 rpm increases almost 9 times, and at rotor speeds 3 times. Microtrauma of Fortuna seeds before harvesting was 4.5%, and after unloading 56.2%, and for Yuvileina seeds 5.1% and 59.3%, respectively. There was no macro-damage to the seeds of either variety before threshing, but after unloading the grain from the combine harvester's hopper, it amounted to 7.3% and 6.2%. Damage by microorganisms, in particular Fusarium in the Fortuna variety after threshing, increased to 40.1%, Helminthosporium to 24.3%, Septoria to 13.6%, Alternaria to 4.6%, and in the Yuvileina variety to 18.2; 13.0%, 11.8% and 3.9%, respectively. During the threshing process, damage, injury and microorganisms affected the quality of the seeds, in particular in the Fortuna variety, the purity at unloading was 96.2%, the number of weed seeds per 1 kg was 281, and the germination rate was 92.1%. The weight in grams was 44.0, the specific weight was 741 g/litre, the raw gluten content was 24.6, and the protein content was 14.7. Accordingly, for the Yuvileina variety, these indicators were 95.0; 170; 94.8; 44.4; 740; 23.1; 13.7. The moisture content of the grain mass after harvesting both varieties was within the range of 14.6 and 14.3%