Properties of Cotton Seed in Relation to Design of a Pneumatic Seed Metering Device

Seed size and its uniformity is an important factor in design and development of seed metering mechanism of any type of seed planter, which helps to optimize the structural parameters for optimum performance. Selected important physical and mechanical properties of three popular hybrids of cotton seeds were studied and its importance in pneumatic seed metering mechanism development discussed. The image analysis technique was used to measure linear dimensions of seed and data was compared and correlated with experimental method. The mean length, width and thickness of the selected varieties of cotton seeds were 8.84, 5.00 and 4.50 mm, respectively considered for the design of cells on the metering plate of cotton planter. The projected area and sphericity of the seed were 36.17, 39.86 and 29.73 mm² and 0.61, 0.64 and 0.67 for CH1, CH2 and CH3, respectively. Strong correlation was observed between experimental and image processing technique in length and width based linear seed dimensions. The average unit mass, 1000 seed mass, volume, true density, bulk density and porosity were varied between 0.079 to 0.098 g, 83.86 to 94.68 g, 89.63 to 99.47 mm³, 1107.68 to1285.43 kg m⁻³, 480.56 to 589.14 kg m⁻³, 46.76 to 53.96% for all the selected varieties. The terminal velocity of cotton seed was varied between 7.46 to 9.86 m/s.