Calculating the Total Costs of the Tractor and the Chisel Plow under Variable Speeds and Depth of Tillage

Factorial experiments were conducted in a silt clay loam soil with a randomized complete block design with three replications for each treatment. This study aimed to calculate machinery unit costs and some indicators during primary tillage, under variable tractor speeds of 1. 8, 3. 5 and 5. 7 km. h-1 and depth of plowing 20, 30 and 40 cm. A higher speed of 5. 7 km. h-1 is associated with higher practical productivity of 0. 9696 ha. h-1; specific productivity of tillage 4309 m. h-1; a volume of soil disturbed 2884 m3. h-1. The best fixed, management, total tractor, total plow and total machinery unit costs were 2. 27, 0. 80, 9. 02, 1. 01 and 10. 04. ha-1 respectively. Additionally, lower fuel consumption was 8. 56 l. ha-1, and the actual time for plowing one hectare was 1. 02 h. The depth of tillage 20 cm recorded a higher productivity of 0. 6412 ha. h-1, the specific productivity of tillage was 2849 m. h-1, less fuel consumption of 7. 74 l. ha-1, less actual time of plowing one hectare of 1. 95 hThe least fixed, variable, management, total tractor, total plow and total machinery unit costs were 4. 32, 4. 71, 0. 89, 9. 94, 1. 94 and 11. 89. ha-1 respectively. All interactions among the treatments were significant. The experiment concluded that the plowing depth has a greater effect than speed on all operating costs of the tractor and chisel plow and performance indicators. The correlations among the indicators studied were direct (positive) and inverse (negative) significantly and were also non-significant.