Determination of the required force to pick cottonseed from four cotton varieties boll in three different harvesting time

Abstract

The cotton plant contains fruits called capsules or bolls, in which the cotton fiber grows, and after the growth stages, the fibers appear through separating the carpels. This research investigated the required force to pick the cottonseed from four cotton variety   (Golestan, Khorshid, Sajedi, and Kashmar) in three levels of moisture (three harvesting times) and three revolutions (1500, 2500 and 3500 rpm). To measure this force, designed and manufactured a device similar to a spindle cotton picker and using the actual needle of John Deere machine 9920. The bolls were tested in different revolution and moisture levels with the device. The results of experiments showed that the cross-effects of variety on speed, harvesting time on variety and harvesting time on speed were significant in picking fibers. Considering the revolution of needle and variety, the most appropriate revolution for the Golestan, Khorshid and Kashmar varieties is 3500rpm, and the most appropriate revolution for Sajedi is 2500rpm. In addition, the results showed that there is a significant difference in the different harvesting times of the khorshid variety. But, there was no significant difference in Golestan and Sajedi varieties between different harvest times. Kashmar variety showed the strongest force in the first harvesting time and the weakest force in the third harvesting time. However, the minimum picking force was obtained for Golestan variety as 0.399N at 2500rpm; in different harvesting times, the khorshid variety had the minimum force (0.251N) and the Golestan variety had the maximum force (0.891N) during the first harvesting time.