Plowing is the most complicated and energy consuming tillage process in agricultural soils. One of its main goals is to obtain a soil hulk density optimal for the growth of plants. The plowing problem has been considered theoretically in the present paper and it was assumed that the clod undergoes four loading processes during plowing. Two of them are bending deformations whereas the other two can be represented by rotations. Different moldboard shapes (circle, ellipse, parabola and hyperbola) are assumed and the moldboard shapes together with the plow bottom action, soil mass deformation, clod formation and motion over the moldboard are introduced in the form of the kinetic equations. They can be used for the prediction of dynamical effects and volume changes resulting in the prediction of the final hulk density. Theoretical consideration have been illustrated using figures and experimental data.