Tandem Disk Width of tandem disks, blade diameter and the distance between blades have tended to increase in recent years. Increases in blade diameter and spacing have led to herbicide performance problems due to excessive operating depths. Conical blades are not suitable for herbicide incorporation because they cut and invert soil rather than mix it. This results in burial of herbicide rather than a uniform mixing. Spherical blades cut, invert, and mix the soil and herbicide.
Incorporation is about one-half the depth of operation.
Poor incorporation often results because more soil is thrown out by the front gang than returned by the rear gang. More uniform incorporation can be achieved by adjusting the angle of the disk gangs so that soil thrown by the front and rear gangs are equal. Often, the front gangs run deeper than the rear gangs which results in burial of the herbicide. Adjustment made on a tandem disk. When using a disk for the second pass on a double-incorporation program, operating depth should be reset.