Engineering Properties of Paddy and Wheat Seeds in Context to Design of Pneumatic Metering Devices

Engineering properties play important role while designing of metering devices of the planter/seed drills. Present investigation was conducted to study the change in engineering properties of paddy (Kranti (PV1) and Pusa1121 (PV2)) and wheat (HI1544 (WV1) and Lokwan (WV2)) seeds due to soaking in water for predetermined duration. Geometric mean diameter of PV1, PV2, WV1 and WV2 was ranged between 3.89 and 4.07 mm, 3.87–4.14 mm, 4.03–4.59 mm and 4.18–4.61 mm, correspondingly due to soaking. Sphericity with aspect ratio of PV1, PV2, WV1 and WV2 seeds were varied as 48.43–49.56 with 0.41–0.42, 32.03–32.07 with 0.2, 60.68–64.12 with 0.51–0.58 and 57.29–60.67 with 0.46–0.52, respectively. Thousand seed weight of PV1, PV2, WV1 and WV2 was increased from 27.80 to 34.88 g, 28.64–35.91 g, 45.68–67.6 g and 48.21–71.13 g, respectively. Bulk and true densities of PV1 and PV2 were increased from 626.49 to 661.98 kg/m 3 and 1150.83–1322.45 kg/m 3 and 540.35–562.15 kg/m 3 and 1376.76–1412.58 kg/m 3 , respectively, for dry to 2 days soaked seeds. Bulk and true densities were 833.06–676.91 kg/m 3 and 1388.09–1258.84 kg/m 3 for WV1 while 816.18–669.85 kg/m 3 and 1647.7–1485.62 kg/m 3 for WV2. Porosity of PV1, PV2, WV1 and WV2 was varied from 45.48–49.87%, 60.61–60.17%, 39.91–48.02% and 50.44–56.55%. Angle of repose of PV1, PV2, WV1 and WV2 was ranged as 30.33–38.13 ο , 27.78–34.15 ο , 29.22–37.97 ο and 32.42–38.51 ο , respectively. On wooden platform, static coefficient of external friction was varied as 0.56–0.62, 0.45–0.53, 0.38–0.65 and 0.41–0.69 for PV1, PV2, WV1 and WV2 seeds, while on mild steel corresponding values of coefficient were 0.37–0.56, 0.40–0.51, 0.33–0.68 and 0.37–0.75. Coefficient on plastic platform was varied as 0.34–0.41, 0.36–0.41, 0.34–0.67 and 0.29–0.63 for PV1, PV2, WV1 and WV2 in same order. Terminal velocity values for PV1, PV2, WV1 and WV2 were ranged between 6.5 and 8 m/s, 6.2–7.6 m/s, 7.4–9.10 m/s and 7.5–10.1 m/s, respectively. Statistical models with ANOVA and multiple pair wise comparison also determined change of the seeds behaviour for soaking conditions.