abbas mahdi-nia

The most important limiting factors in reduction of mechanization degree of cotton harvesting are access to suitable harvester for a specific planting pattern and lack of suitable varieties. In order to evaluate the performance of cotton picking combines in conventional planting patterns, three cotton picking combines (self-power three-row cotton picker that was designed and built in Khorasan Razavi Agricultural Research Center, self-propelled two-row cotton picker and tractor-mounted two-row cotton picker) were studied. In this context , the effects of type of cotton picker (three levels), forward speed (2.1, 3.4 and 4.8 km/h) and cotton variety ( Khordad and Varamin) were investigated and the effect on parameters such as weight percentage of cotton losses at first and second picking stages, weight percentage of cotton waste, efficiency, effective field capacity and fuel consumption were recorded. The results showed that self-propelled three-row cotton picker had the highest effective field capacity (0.48 ha/hr.) and the lowest efficiency percent (64.9%) as compared to the other cotton pickers. The highest efficiency (74.68%) belonged to self-propelled two-row cotton picker. The lowest weight percentage of cotton losses (7.87%) was obtained at 1.2 km/hr. forward speed. The economic analysis and comparison of cotton pickers showed that the self-propelled three-row cotton picker, due to lower initial cost as compared to others cotton pickers, had the lowest period of initial cast return (3.29 years).