The two-bottom moldboard plow is a common, smaller tool used to turn the soil, burying crop residue and weeds to prepare a clean seedbed. This process of soil inversion and aeration helps manage pests and incorporates organic matter into the soil profile. The “two-bottom” designation means the plow has two moldboard assemblies, each cutting and turning a separate furrow slice.
Connecting the Plow and Initial Setup
The first step involves securely attaching the plow to the tractor, typically using a three-point hitch system. Align the tractor’s hitch arms with the plow’s lower pins and secure them with lynchpins, ensuring the lift arms are fully engaged. Next, the top link is connected between the tractor and the plow’s mast, which controls the implement’s fore-and-aft pitch.
Once connected, the plow needs initial side-to-side leveling. With the plow resting on flat ground, adjust the threaded right-hand lift arm until the plow frame is level horizontally. This ensures both plow bottoms cut to the same depth and width. All subsequent calibration relies on this foundational level setting.
The plow must also be centered behind the tractor to ensure the front bottom cuts the correct width. For most two-bottom plows, the inside edge of the front bottom should align closely with the inside edge of the tractor’s right rear tire. This alignment ensures the plow takes its full designed cut without leaving unplowed strips or causing undue side-draft.
Calibrating Depth and Draft
Proper calibration is necessary for an efficient and quality result. The general rule for depth is roughly half the width of the furrow slice; for a 14-inch plow, the depth should be near 7 inches. This depth is initially set using the tractor’s hydraulic position control lever, which raises or lowers the three-point hitch.
The fore-and-aft leveling, or pitch, is controlled by adjusting the length of the top link. Shortening the top link lowers the plow’s front and increases the “suck,” helping the plow penetrate hard ground. Conversely, lengthening the top link raises the front, which prevents the plow from digging too deep in very soft soil. The goal is to set the pitch so the plow runs level from front to back once fully engaged in the soil.
Draft refers to the resistance the plow creates as it moves through the soil. Modern tractors use a draft control system, often through the top link, which automatically raises the plow slightly if the draft force exceeds a set limit, preventing stalling. The width of cut must be finalized so the plow’s landside runs straight against the furrow wall without causing the tractor to pull hard to one side, known as side-draft.
Side-draft is minimized when the center of the plow’s resistance aligns with the tractor’s line of pull. If the plow continually pulls the tractor to the right, adjust the plow attachment point slightly to the left, or vice versa. Correct leveling and pitch ensure the plow slices cleanly and the moldboards turn the soil over completely.
Plowing Patterns and Field Execution
Once the plow is calibrated, field execution requires a systematic approach. The two primary methods for starting a field are the “back furrow” and the “dead furrow” patterns.
The back furrow method starts in the center of the field by throwing the first two furrows toward each other, creating a raised ridge. This pattern is often used to eliminate a previous low spot. The dead furrow method begins at the field’s edge, throwing the first furrow toward the boundary. Subsequent passes continue toward the center, leaving an open trench where the last two rows meet. This pattern is useful for fields with a slight slope, as the dead furrow can aid in drainage.
Regardless of the starting method, the plow must be driven at a slow, steady pace, typically in a low gear, to ensure the soil is fully inverted and laid over uniformly. Maintaining straight rows is simplified by aiming for a fixed point on the far side of the field. At the headlands, the operator should lift the plow just as the front bottom clears the end of the last furrow, turn the tractor, and drop the plow back into the soil to begin the return pass.
Addressing Common Plowing Problems
A common issue is the plow clogging with residue, which happens when the moldboards or coulters are rusty or not “scouring.” The moldboard surface must be shiny and smooth to allow the soil to slide off cleanly. Plowing in abrasive soil until the rust is removed is often a quick fix. Adjusting the coulters—the cutting wheels in front of the moldboards—to cut slightly deeper and further into the unplowed land helps slice through heavy trash.
Uneven depth is frequently caused by a side-to-side leveling issue. If the rear bottom is plowing deeper than the front, adjust the right lift arm to raise that side of the plow. If the tractor pulls hard to one side, it indicates poor side-draft adjustment, requiring a slight modification to the hitch or the plow’s landside to align the pull with the center of resistance.
If the soil is not completely turning over, it suggests an incorrect fore-and-aft pitch or insufficient speed. Shortening the top link to increase the angle of attack improves soil inversion, ensuring crop residue is fully buried beneath the new furrow slice. Checking that the plow shares are sharp and not excessively worn is necessary, as dull components cannot penetrate and cut the soil cleanly.