Method for Determining Grain Losses Behind the Combine Header and Thresher During Soybean Harvesting

It was noted that in waterlogged soil conditions, the existing methods for assessing field grain losses when harvesting soybeans using low-cut headers are not always suitable. (Research purpose) To improve the methodology for assessing soybean losses during harvesting in the waterlogged soil conditions, using the possibility of sampling them separately behind the header and thresher of the combine. (Materials and methods) The methodological approach was based on: the impact of crop heterogeneity; the principle of adequate accuracy in loss assessment, regardless of soil conditions during harvesting; accessibility, simplicity and minimal labor intensity of the method; the possibility of differentiating grain losses behind the header to identify their main sources. Three main loss zones were identified and the characteristics of their sources were considered. The authors presented a scheme for applying square metal frames with a 1-meter side length on crops and on a harvested field area after the passage of the combine. The authors described the sequence of laboratory and field assessment and formulae for determining natural grain losses, losses behind the header and their types, soybean losses behind the thresher and total losses behind the combine. (Results and discussion) A methodology for soybean loss assessment was developed and tested during the trial of the Case IH AF6140 combine with a New Holland 740CF-30DD(SF) header. It was found out that this combine meets all the norms for soybean grain losses at a combine speed of 6 kilometers per hour. Loose grains were revealed to be the largest share of losses behind the header. To further mitigate losses, it was proposed to control the number of reel revolutions. (Conclusions) We have developed a technical approach and an algorithm for grain loss assessment with the use of rigid metal frames, which ensures high reliability, efficiency and lower labor intensity when considering losses and calculating actual and permissible (from biological yield) values for the specific and relative soybean losses behind a header and combine harvester as a whole.