Economic efficiency of two-stage separation of maize hybrid seeds

Topicality. During harvest and post-harvest processing, maize seeds are a mixture that consists of seeds of different quality, size, and weight. Therefore, it is necessary to separate the seeds, i.e. divide the mixture into separate homogeneous fractions. The number of fractions varies depending on the evenness of the mixture and separation methods. Aim. To establish the pattern of fractional separation of maize hybrid seeds, develop methods for their cleaning and sorting in post-harvest processing technologies, and calculate the economic efficiency of a new two-stage separation method. Materials and methods. In the experiments, we used maize hybrids developed by the Institute of Grain Crops of the NAAS, which were separated on sieves with round and oblong holes. The two-stage sepa-ration method was as follows: the first stage, the sieve of grain separator in the throughs and tailing mode separates the mixture into two groups of seed (the sieve holes with a diameter of 8–9 mm or ob-long holes with a width of 5.5–6 mm and a length of 20 mm); the second stage, a grain separator (one or two) sorts each group into a given number of seed fractions (the sieve holes with a diameter of 5–8 mm or oblong holes with a width of 3.75–4.50 mm). Results. Our research has determined the features of separation of the studied hybrid seeds according to various traits and methods. Firstly, the field germination of the seed fractions selected on the trait of seed width was higher compared to seeds selected on the trait of seed thickness. Secondly, separation on the trait of seed thickness is effective only for increasing seed uniformity. The new two-stage separation method was tested in the Research Farm LLC Agrofirma ART Zolotoi Kolos (Dnipropetrovsk region) during separation of maize hybrid seeds harvested in 2018–2020. As a result of fractional separation by a new method, it was obtained the standard seeds of maize hybrids with a germination rate of 95–96 %, a growth rate of 85–90 % without any seed injury. Conclusions. In the technologies of post-harvest processing and pre-sowing preparation, it is recommended to use a two-stage separation method when the seeds are divided into two sowing groups with further separation into the required number of fractions. Separation is carried out on flat sieves with a size of holes depending on the shape of the seeds. The productivity of grain separators increased by 20 %, and the specific energy consumption decreased by 8 % due to the two-stage separation. The overall economic effect was in the form of energy savings of UAH 1.8 per ton of seeds. In addition, the net profit from sowing with high-quality seeds was 6,233 UAH per 1 ha. Key words: maize, hybrids, separation, field germination, economic efficiency.