Aerodynamic separation and its influence on seed quality of corn hybrids

Abstract

Heterogeneity of seeds by physico-mechanical parameters is intrinsic to corn, which prevents implementation of aerodynamic separation of seeds into industry.

Aim. Ascertainment of aerodynamic separation peculiarities, determination of physico-mechanical properties and particle size distribution of corn hybrid seed material as a separation object.

Methods. Simulation of grain separation process and assessment of its quality in laboratory and field experiments. By sailing capacity the source material was separated into three main fractions: light, heavy and medium in a laboratory pneumatic seed classifier additionally equipped with an aspirator.

Results and Discussion. The process of aerodynamic separation of corn hybrid seeds is not stable an unable to provide high-quality separations into fractions. The yield of the same fraction for the hybrid Ushitskiy 167SV seeds varied from 16.2 % to 24.2 %. The measured values of caryopsis linear parameters suggest that corn seeds from light and heavy fractions differ rather by the ratio between length, width and thickness, by which the caryopsis shape can be judged, than by boundary values of these parameters. Light fraction seeds are flat oblong, the ratio length:width:thickness is 1.18 : 1.00 : 0.56. Heavy fraction seeds are more compact with the ratio of 1.06 : 1.00 : 0.73. The analysis of seed physico-mechanical parameters refutes the assumption that upon seed distribution fractions distinguishing by specific gravity are formed. Unlike specific gravity the volume and mass of 1,000 seeds proportionally increased up to 15.9 % in the heavy fraction as a result of aerodynamic separation, and in the light fraction of some hybrids they decreased down to 7.9-9.4 % as compared to the control. The analysis of sowing qualities revealed no direct correlation between sailing capacity and germinating ability of corn hybrid seeds. A significant increase in the laboratory and field germinating ability (by 11 % – 4 %) was obtained both in the light and in the heavy fractions.

Conclusions. Taking into account complexity of the process and instability of distribution of corn hybrid seeds into fractions, aerodynamic separation procedure for grading purpose requires further investigations, and its application is more expedient to perform in a cleaning mode.