Time scale, delta derivatives, nabla derivatives, self-adjoint boundary value problem, symetric Green’s function.

Abstract

Metering device is the most important component of a seed planter which effectively influences on crop yield and yield components. Therefore
it is necessary to determine important parameters that affected on the performance of metering device. In this study a fluted-roller seed metering
device with upside feed mechanism was used and effects of such important parameters as variety (Hashemi, Binam, Hasani), length (3,4,5,6 and 7
cm) and rotational speed (5,10,15,20 and 25 rpm) of metering unit was investigated on the seed flow rate, variations of seed flow rate and percent of
damaged seed. Results of this study indicated that the seed flow rate of pre-germinated paddy significantly (P<0.01) affected by variety, rotational
speed, length of the fluted-roller metering unit and their interactions. For each type of paddy variety, the seed flow rate increased with increasing in
length and rotational speed of metering device from 3 to 7 cm and 5 to 25 rpm, respectively. The average seed flow rate of Hashemi (2.91 g s) was
higher than Binam (2.66 g s) and Hasani (2.44 g s). The lower variations of seed flow rate were achieved as the rotational speed and length of
the metering unit increased. There was a significant effect of rotational speed (P<0.01) and variety (P<0.05) on the damaged pre-germinated seeds.
The percent of damaged was varied from 6.56 to 10.69 %, 5.98 to 13.25 % and 5.91 to 12.73% for Hashemi, Binam and Hasani, respectively as the
rotational speed of metering unit increased from 5 to 25 rpm.