Maintaining Crop Residue with Different Tillage Systems
Tillage implements leave various levels of crop residue on the soil surface. The effectiveness of seven tillage systems at protecting crop residue is described below.
Moldboard Plow-Plus secondary tillage (MP+): Moldboard plowing followed by one or two secondary tillage operations with a field cultivator or disk before planting. This system is an aggressive tillage practice that often leaves less than 10 percent of the surface covered with crop residue after planting.
Chisel Plow-Plus secondary tillage (CP+): Fall chisel plowing or “ripping” to a depth of about 10” plus spring secondary tillage with a field cultivator or disk. This tillage practice is quite aggressive and can reduce crop residue, especially after soybeans, to levels that are inadequate for erosion control.
Shallow spring tillage: Single pass with a field cultivator (SFC) in spring before planting corn after soybeans or with a tandem disk (SD) before planting soybeans after corn. These are less aggressive tillage systems that may leave adequate residue after planting when SFC follows soybeans and SD follows corn.
Ridge-Till (RT): Tillage is limited to that performed by the planter (ridge leveling) and one or two in-season row cultivations (ridge building). Preformed ridges provide a drier and warmer seedbed at planting. Adequate levels of crop residue remain after planting.
Strip-Till (ST): Strips about 4 to 6” wide and 7 to 8” deep matched to the row-spacing of the planter are prepared in the fall with mole fertilizer knives mounted on a tool bar. Fertilizer P and K can be injected directly into the strip at the time of strip tillage. Corn is planted into the tilled “residue free” strip without any secondary spring tillage. Adequate levels of crop residue remain after planting.
Deep Zone-Till (DZT): Deep slit tillage to a depth of 15 to 20” is done in the fall using a narrow subsoil shank on 30” spacing. The crop is planted directly above the deep “residue-free” slit zone. This tillage system often buries more residue than the strip-till system and may not leave adequate residue following soybeans.
No-Till (NT): The planter performs all seedbed preparation including clearing residue away from the seed rows. The crop is seeded into a relatively “residue free” zone. Maximum surface residue coverage occurs with this system.
 Chisel plowing fragile soybean residue does not leave sufficient soil cover for protection against erosion on sloping soils. |
 Strip tillage removes crop residue from only the row area. |
 Chisel plowing heavy corn residue leaves some residue for protection of soil from erosion. |
 No-till leaves the maximum crop residue for soil protection. |
