Improvement of the Soybean Harvesting Process as a Way to Increase the Quality of Seeds

Abstract

The quality of seeds is the most important factor in increasing the yield of agricultural crops, including soybeans. However, on average, up to 20–25% of soybean seeds sown in the Amur oblast are substandard. At the same time, one of the main reasons for the decline in the quality of seed material is significant crushing and damage of soybeans during harvesting and processing. Up to ten different brands of combines, which allow a high degree of crushing of bunker grain, are used in harvesting soybeans in the Amur oblast. The crushing of grain by combines of different brands varies in the range from 6.9 to 15.1%. Combines of Russian and foreign production are mainly single-beater drum by design and collect the threshed soybean grain in one bunker, while they do not separate seeds according to the biological diversity inherent in soybeans. As a result, soybean yield losses reach 2.7–3.3 c/ha. In order to reduce grain losses from the crushing and obtaining of high-quality seeds, a new device based on a two-stage threshing combine with double-flow cleaning and with two bunkers was developed. The study of the operating modes of the threshing and separating device for threshing, separation, and damage of soybean seeds along the length of the combine thresher was carried out. The goal of this study was the selection and preservation of the part of the biologically valuable and high-quality soybean seeds from the crushing during combine harvesting of soybean with reduced grain moisture (less than 12%). The conducted research with the use of the complete factorial experiment method and processing the results allowed creating mathematical models of separation and seed damage. Based on this model, a nomogram for determination of separation and the content of damaged soybean seeds was constructed. Damaged seeds were obtained in the zone of the first beater drum, depending on the technological adjustments of the threshing apparatus, grain feed, and grain moisture.