The effect of some crop and soil parameters on mechanical damage and Mechanical properties of potato during and after harvesting

In this study, the effect of variety, harvesting time and soil moisture on mechanical of samples, during harvest and storage time of two month. Moreover, the effect of these parameters on rheological properties such as rupture energy, Strength against penetration, and stress relaxation has been investigated using factorial design. The results showed that variety, harvesting time and soil moisture have a significant effect on potato damage during harvesting and after storing time. From this point of view, Agria, Sante and Fontane varieties have the most damages respectively. The maximum amount of damages was related to soil moisture with situation of wilting point (9 percent), and minimum amount of damages was related to soil moisture with field capacity (15 percent). During harvesting the Max and Min amount of losses were obtained during early harvesting (middle of September) and late harvesting (middle of October), respectively.
The maximum and minimum energy required for rupture was 87.22 and 73.34 E-3 joule related to Fontane and Agria respectively. Strength against penetration was 6.76, 6.56 and 6.26 N for Fontane, Sante and Agria respectively. Max amount of stress relaxation was 72.36% for Fontane by Santa and Agria with 71.20 and 69.04 percent.