Physical and mechanical properties of ridging radishes in Northern China

Based on the field and lab measurement on the ridging green and red radishes in harvest time in north China, the physical and mechanical properties of radishes, such as geometric characteristics, the optimum parameters combination of the loosening location, and pulling force, were explored. The mathematic statistics method was employed to analyze the main geometric properties. The variation range and distribution frequencies of main geometric properties indexes of the green and red radishes were found out. The tensile test was carried out to measure its mechanical properties, such as cohesive strength between stem and root of radishes, pull force in harvest, and the data were analyzed by means of software of the Design-Expert Version 6.0.10. The experimental results indicated that the cohesive strength between the stem and the root of the green radish and the red radish were in the range of (2.45±1.23)105 Pa and (2.17±1.08)105 Pa, and the minimum anti-pull force was 90 N and 110 N, the maximum pull force for the green and red radishes in condition of natural growth in harvest were in the range of (191±113.8)N and (197±107.2)N, respectively. Optimum parameters combination of the loosening location were that the depth was from 15 to 26 cm, and the distance was from 10 to 20 cm, using pull method to harvest the green radish, and that the depth was from 18 to 24 cm, and the distance was from 12 to 16 cm, using pull method to harvest the red radish. The study provides theoretical data for designing radishes harvester.