Determination of boll picking force and energy in the four cotton variety

The bolls which are used in cotton in this research was separated from pedicles randomly; and the effects of loading speed and moisture content of boll on force and energy, that is needed for harvesting at four variety of bolls (Golestan, Khorshid, Sajedi, and Kashmar) in the different harvesting of cotton were was analyzed by using the traction-pressure device. The results showed that the effects of variety and speed of loading, and also mutual effects of variety in the speed of loading and harvesting time in variety has meaning on the force of picking in 1% level;, but the effect of harvesting time and mutual effect of harvesting time in the speed of loading is meaningless. The most picking force was 22.7N (variety of Kashmar, loading speed=10mm/min); and the less force of picking was 4.922N (variety of Golestan, loading speed=5mm/min). Also, the most force of picking in first harvesting belonged to Kashmar variety (23.567N), and the less force of picking in the third harvesting was also belonged to Golestan variety (5.967N). The effects of harvesting time, variety, the the speed of loading and mutual effect of harvesting time on variety in 1% level, and also the mutual effect of harvesting time on the speed of loading in 5% level has meaning on picking force; but the effect of variety on the speed of loading is meaningless. The maximum and the minimum energy of picking was respectively 96.45mJ/mm (Kashmar variety, first harvesting) and 26.476 mJ/mm (Golestan variety, third harvesting).