تعين نيرو و انرژي لازم براي كندن غلاف نخود بعنوان معياري براي ارزيابي مقاومت به ريزش

Determining the Force and Energy Required for Picking Chickpea Pod as a Criterion for Estimatation of Resistance to Shatter

In this study, the effect of moisture content, loading velocity and direction of applied force were studied on force and energy required for picking pods in three varieties of chickpea (Bivanij, Kaka, and Jam). An Instron testing machine was used for pulling off the pods. All factors indicated a significant effect on force and energy required for picking chickpea pods. The force and energy required for picking increased with a decrease in moisture content from 50% to 25%, but decreased significantly afterwards to become minimum at moisture content of 8%. The mean value for force and energy required for picking pods with 25% miosture content was 6.82 N and 19.40 mJ, respectively. Corresponding values at moisture content of 8% were equal to 1.19 N and 4.93 mJ, respectively. So, estimation of the resistance to shatter based on the force and energy shows that at 25% moisture content, chickpea pods show the most resistance to shatter, and so it is the best time to harvest the product. But, harvesting of the product at this moisture content level requires the most power. With an increase in velocity, the amount of required force and energy decreased significantly. The mean values of force and energy required for picking Bivanij dryland variety pods were 4.7 N and 14.25 mJ respectively, being significantly higher than those for the other two varieties (Kaka and Jam). Therefore, it is expected that this variety (Bivanij) be more resistant to shattering than the other two varieties. The force and energy required for picking pods in downward direction was significantly lower than that in upward direction. This difference was not significant for crop at 8% moisture content.