They give varying degrees of weed control, so a pre-seeding herbicide application may not be needed. However, they may also create a seedbed for weed seeds and volunteer seeds from the previous crop. High disturbance openers may require additional seedbed finishing to cover the seed and to improve weed control. In a no-till cropping system, planting is the only operation which disturbs the soil. Only 25 to 35 per cent of the soil surface is disturbed.
Most openers require that much disturbance to place the seed and fertilizer into a seedbed.
Many farmers, however, strive for less than 25 per cent disturbance. No-till is similar to low disturbance direct seeding except that direct seeding systems allow some tillage to deal with unusual conditions. In direct seeding systems, residue management begins at harvest. Residue clearance is the ability of planting equipment to allow crop residue to pass through without bunching. Ground openers and shanks are shaped to prevent dragging and subsequent bunching of straw residue.