الفهرس 
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Abstract
The experiments were carried out at El-Maamoria village- El-Gamalia region, Dakhlia Governorate during onion harvesting season 2008-2009. The main objective of the present study is to develop a combine machine for harvesting and collecting onion crop with achieving the following: (Decreasing harvesting costs of onion crop, decreasing a partial and total damage caused in onion bulbs, decreasing harvesting period and easing of collecting onion crop. This study was divided into two experimental groups that carried out in the same field. The first experimental group Treatments:- 1-Speed ratio was adjusted at four levels (ratio of speed of elevator and forward speed) they were (1.8, 1.55, 1.05 and 0.80) named K1, K2, K3 and K4 respectively. 2- Share tilt angle (digging unit) was adjusted at four angles (10, 15, 20 and 25 degree) named T1, T2, T3 and T4 respectively.3-Share depth (digging unit) was adjusted at four levels (4, 5.5, 7 and 8.5 cm) named D1, D2, D3 and D4 respectively. Results of The first experimental group: the best results of harvesting efficiency and damage percentage was at speed ratio 1.8, share depth 8.5 cm and share tilt angle 25 degrees and the best results of fuel consumption was at speed ratio 1.8, share depth 4 cm and share tilt angle 10 degrees. The second experimental group Treatments:- 1- Soil moisture content ( 24.5% and 20.5%) is named M1 and M2 respectively. 2- Rear angle elevator, (0, 5, 10 and 15ه) are named R1, R2, R3 and R4 respectively. 3- Speed vibrator 1, 1.3, 1.6 and 1.9 m/s are named V1 ,V2 ,V3 and V4 respectively Results of The first experimental group: the best results of separation losses was at moisture content 24%, ray separator rear angle 15 degrees and vibrator speed 1 m/s and the best results of cleaning efficiency was at moisture content 20%, ray separator rear angle 0 degree and vibrator speed 1.9 m/s.