الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Field experiments were carried out at Al-Shabab project farm, Al-Esmaalia Governorate through the winter season of 2013 to compare between some different potato harvesting machines in small holdings (agitator potato digger, elevator potato digger and chisel plow) and evaluate their performance under field conditions during the harvesting operation of potato crop (Diamant variety). The objectives of the present investigation are to: 1. Compare the performance of three different potato harvesting machines Suitable for small holdings. 2. Optimize some different operating parameters affecting the performance of potato harvesting machines. 3. Evaluate the performance of potato harvesting machines from the economic point of view. The experimental area was about 12 feddans divided into four equal plots (3 feddans each) with dimensions of (252×50) m for four different soil moisture contents of 9, 11, 13 and 16 % (d. b. ). Each plot was classified into three equal sub plots (one feddan each) with dimensions of (84×50) m. In each subplot, one of the following potato harvesting machines was used: 1- Potato elevator digger 2- Potato agitator digger 3- Chisel plow. Each subplot was classified into three equal sub subplots (50×28) m for three different harvesting depths of 22, 27 and 32cm. Each sub subplot was divided into four equal slices (50×7) m to operate potato harvesting machines under four different forward speeds of 1.3, 1.8, 2.5 and 3.0 km/h. Evaluation of potato harvesting machines was carried out taking into consideration field capacity and field efficiency, total tubers losses, power and energy requirements and harvesting cost. The obtained data reveal the following important points: 1- The agitator potato digger followed by elevator potato digger are recommended to be used for harvesting potato because of their higher harvesting efficiency and less of both losses and cost comparing with the chisel plow.2- The proper operational conditions for operating potato diggers are: Forward speed of 2.5 km/h Harvesting depth of 32 cm Soil moisture content of 13 % (d. b.)