Research in cleaning and sorting of ecologically grown white mustard seed

Abstract

The research objective was to obtain a high quality sowing material of ecologically grown white mustard (Sinapis alba) seed. In order to achieve the goal white mustard seed was sorted into fractions based on seed rigidity thus minimizing the amount of weed seed – field mustard (Sinapis arvensis) and rambling smartweed (Polygonum convolvulus) which have similar physical and aerodynamic characteristics to the white mustard. For the purpose of the experiment a basic stationary experimental stand was built. The unit was comprised of: 1) a frame of 3 m height; 2) a seed feed hopper with an adjustable valve; 3) an inclined plane which inclination angle to the horizon was adjustable; and 4) 0.2 m wide and 1.5 m long troughs designed for sorted seed groups. White mustard seed freely fell from the supply tank from the height of 0.5; 1.0; 1.5 and 2.0 m onto an inclined plane with an adjustable inclination angle to the horizon of 25; 30 and 40 degrees. Two types of inclined plane surface were used in testing: wooden and metallic. During the testing white mustard and weed seed was sorted into 7 fractions. With increasing the number of fraction (seed displacement with respect to the horizontal axis), the weight of 1000 seeds (g) and seed density (kg·m-3) was found to increase, however part of higher density seeds (%) was found to decrease. With increase in the number of fraction, the proportion of weed seeds in fractions was decreasing. Optimal results in the research were achieved with 1.24 kg·min-1 white mustard seed flow being supplied from the height of 2.0 m onto a metal plate with the inclination angle to the horizon set to 30º. Seed germination energy (%) and seed germination power (%), when compared to the control, did not decrease and starting with fraction 2 and onwards increased by approx. 10 % (in absolute values).