Improving paddy seed vigor by corona discharge field processing and dielectric separation

Abstract: In order to research the effects of corona discharge field processing and dielectric separation on the vigor of paddy seeds, a corona discharge field processing test was conducted with an arc-shaped electrode at a processing voltage of 15 000, 17 500, 20 000, and 22500 V(DC) for 4 min. The results showed that the vigor of the paddy seeds were significantly improved, and increased initially and then decreased with the processing voltage. The four indexes (the germination potential, the germination rate, the germination index, and the vigor index) got the maximum value at the processing voltage at 17500 V, and increased by 88.5%, 22.2%, 26.9%, and 30.8% in comparison with that of CK. Through the analysis with ANOVA, it was found that the effect of the arc-shaped electrodes on the four indexes of the seeds was significantly (p<0.01) higher than that of the CK at a processing voltage of 17 500 V.In addition, a dielectric separation was performed with a dielectric separator at the different separating voltages of 2 000, 3 000, 4 000, and 5 000 V(DC) when the rotating speed of the separating roller was 25 r/min, and the results also showed that the vigor of each class was significantly different. The vigor of the classⅠpaddy seeds was highest, and the vigor of the class Ⅲ paddy seeds was lowest. The vigor of the classⅠpaddy seeds was significantly (p<0.01) higher than that of the CK. The vigor of the class Ⅲ paddy seeds was lower than that of the CK. That was to say that the separation effect was obvious. The vigor of the classⅠpaddy seeds was significantly increased when the rotating speed of the separating roller was 25r/min and the selecting voltage was 4000 V (DC). The four indexes of paddy seeds with that treatment were increased by 59.4%, 20.6%, 33.3% and 45.2% in comparison with that of CK. Through the analysis with ANOVA, it was found that the effects on the four indexes of the seeds were significantly (p<0.01) higher than that of the CK.On the other hand, it was also found that the vigor of class Ⅱ and class Ⅲ paddy seeds which were firstly processed with the corona discharge field and then separated with the dielectric separator under the above optimum conditions (17 500 V and 4 min for the corona discharge field processing, 4000 V and 25 r/min for the dielectric separator) were significantly higher than that of the paddy seeds which were solely processed with the dielectric separator. The vigor of the class Ⅱ paddy seeds was significantly (p<0.01 or p<0.05) higher than that of the CK. The vigor of the class Ⅲ paddy seeds was higher than that of the CK. These results will provide a foundation for developing a new processing and separating device. It has a great significance for agricultural production. The number of the generation of the paddy seeds was recorded from the 5th day to the 10th day as well. It was found that a corona discharge field and dielectric separation increased the speed of germination of paddy seeds. It also suggested that the dielectric separation electric field treatment was also a process of electric field treatment.