Evaluation of Physico-Mechanical Characteristics of Different Paddy Cultivars Grown in Humid Subtropical Region of Eastern China

Background: Paddy during various stages i.e. loading, transportation, storage, handling etc. occurs severe losses, which can be reduced by designing appropriate post-harvest machineries using physico-mechanical properties. Objectives: The study aimed to assess the variation in physico-mechanical properties of thirteen different paddy cultivars. Methodology: The study was carried out at the College of Engineering, Nanjing Agricultural University, China. Thirteen different freshly harvested paddy cultivars were collected from Nanjing. Collected paddy cultivars before experiment were cleaned removing extraneous materials. Paddy cultivars were sealed polythene bags, and were then kept in refrigerator at a temperature of 5 ºC for 7 days for uniform distribution of moisture. The required amount of samples from each cultivar was accordingly taken for evaluating their physical and mechanical properties. Results: The results when assessed were statistically different (p?0.05) from each other. The average values of different paddy cultivars for length, width, thickness, geometric mean diameter, arithmetic mean diameter, square mean diameter, equivalent diameter, surface area, volume, sphericity, aspect ratio, thousand kernel weight, bulk density, true density, porosity, hardness and toughness (for both horizontal and vertical orientations) were calculated to be 7.94mm, 3.32mm, 2.26mm, 3.84mm, 4.51mm, 2.56mm, 3.64mm, 46.53mm2, 29.74mm3, 0.49%, 0.42, 28.64 gm, 568.31 kg m-3, 1225.20 kg m-3, 54%, 46.09 N, 14.75 N, 16.06 mJ and 6.90 mJ respectively. Conclusion: A wide variation was observed for each parameter while comparing different paddy cultivars. This wide variation in result will negatively affect the performance of the equipment and machinery being used for post-harvest practices. The study concludes that it is essential for industries involved in equipment design and machinery production, as well as end-users responsible for their implementation, to take into account these substantial differences among cultivars when making their decisions.