An Investigation of the Effects of Forward Speed, Cylinder Rotation, and Clearance between a Combine’s Cylinder and Concave on Wheat Kernel Breakage and Seed Germination

The effective factors of forward speed, cylinder rotation, and clearance between a combine’s cylinder and concave on wheat kernel breakage and seed germination were studied in Karaj area using a 955 model John Dear combine. This study was conducted on three levels of adjustment for each of the variables, 1.2, 1.8 and 2.5 Km/hr for forward speed, 800, 900, 1000 rpm for cylinder rotation as well as 15, 20 and 25 mm for the clearance between cylinder and concave. Results indicated an increase in kernel breakage and a decrease in seed germination to arise from a decrease in forward speed, increase in cylinder rotation and decrease in clearance between cylinder and concave. The interaction between forward speed and cylinder rotation indicated a least kernel breakage of 5.47% along with the most seed germination of 96.61% arising from a forward speed of 1.8 Km/hr together with cylinder rotation of 800 rpm. Also, an interaction between cylinder rotation, and cylinder concave clearance indicated a least kernel breakage of 5.38% at 900 rpm and 25 mm for the former and latter variables respectively. A maximum seed germination of 96.6 % was observed for the same condition of cylinder rotation and clearance between cylinder and concave. Interaction between forward speed, and cylinder concave clearance was observed to be non-significant (p<5%). Also, non-significance was observed in interaction among forward speed, cylinder rotation, and cylinder concave clearance (p<5%). The results revealed the adjustments 800-900 rpm, 1.8 Km/hr and 25 mm for cylinder rotation, forward speed, and cylinder concave clearance respectively, while using a 955 model John Deer during wheat harvest in Karaj.