A.J.Nassir M. N. Ramadhan S.D .Mohssein
Machines and Agricultural Machineries Dept./ Agric. College/ Basrah University/ Basrah/ Iraq.
:Field experiment was conducted at the fields of Agricultural College- University of Basrah, Karmatt-Ali campus according to randomized complete block design (RCBD) with a split plot arrangement of the treatments to study the effect of three forward speeds (1.30, 0.80, 0.41 m.sec-1) and three plowing depths (25, 15, 10 cm) on the field performance indicators i.e. draft force ,drawbar power , specific resistance, mean weight diameter (MWD), plowing efficiency and degree of plowing in silty – clay soil. The forward speeds was the main plots and tillage depths as sub-main plots. The soil bulk density was (1.30 Mg.m-3) and content moisture was (10.50 %). The results showed that the increase in forward speed from 0.41 to 1.3 m.sec-1 led to a significant increase in draft force, drawbar power ,specific resistance ,plowing efficiency by (20.40, 106.62, 429.44, 109.45%), respectively, while the mean weight diameter (MWD) and the degree of plowing were decreased by (4.7 0.36%), respectively .While increasing plowing depth from 10 to 25 cm led to a significant increase in draft force, drawbar power and mean weight diameter (MWD) by (58.97, 49.50 , 82%) respectively and decreasing in specific resistance, plowing efficiency and degree of plowing by (46,96 ,36.5, 48.8 %) respectively. The interaction between forward speed and plowing depth was effected significantly on the field performance indicators. The highest level in draft force and drawbar power were 24.45 kw 22.84, kN respectively at forward speed 1.3 m.sec-1 and plowing depth 25 cm and highest level in specific resistance was 115.95 kN .m -2 .The best value of mean weight diameter (MWD) was 27.16 mm at forward speed 1.3 m.sec-1 and depth 10 cm and best value of plowing degree was 87% in forward speed 0.41 m.sec-1 and the depth of plowing 10 cm while the best plowing efficiency value was 81% at forward speed 1.3 m.sec-1 and depth of plowing 10 cm .
Key words: chisel plow, draft force, specific resistance, draft power, mean weight diameter, degree of plowing, plowing efficiency.
AL-Muthanna Journal of Ag ricultural Scie nce s | Volume : 4 | No : 1 | 2016