الفهرس 
Factors related to the blades
Theoretical considerationOnly 14 pages are availabe for public view
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Abstract
The main purpose of this study is to develop a locally spreader to spread the different fertilizer types with rates can be automatically controlled. For this reason an electronic circuit has been constructed to control the feed rate of fertilizer with respect to forward speed of the machine. The developed system was evaluated under controlled and field conditions. The first stage of the controlled condition was to study the effect of the spinner type (cone and flat), numbers of spinner blades (4 and 6), rotational spinner speed (360, 480, 600 and 750 rpm) and fertilizer type (powder and granular) on the distribution pattern of spreader. While, The second stage of tests was done under the optimum values obtained from the first stage tests to focus the effect of the spinner diameter (200 and 300), feeding rate (100, 150, 200 and 250 kg/fed.) and blade angles (10, 0 and +10 degree) on the distribution pattern. However, the modified spreader was evaluated under field conditions during fertilization of wheat crop comparing with common centrifugal spreader (traditional). The obtained results concluded that: <U+2022> The lowest values of coefficient of variation were obtained at 600 rpm flat spinner speed and 4blades. <U+2022> The feed rate of 150 kg/fed gave the best distribution pattern for granular and powder fertilizers. But for coarse fertilizer, the feed rate of 100 kg/fed gave optimum distribution pattern at all blade angles and spinner diameters. <U+2022> The highest values of uniformity and symmetry coefficients were obtained at blade angle <U+2013>10 degree when using coarse and powder fertilizer, In case granular fertilizer, blade angle of 0 degree (radial) gave the best distribution pattern. <U+2022> At all feed rates, blade angles and fertilizer type, 30 cm spinner diameter gave best distribution pattern. <U+2022> Using modified spreader increased the total straw and grain yields by 16.82% and 14.41%, respectively comparing with traditional spreader.