strip cropping

Strip cropping divides a field into alternating bands of different crops, typically running along contour lines or perpendicular to the slope. One strip might grow corn; the next, alfalfa or soybeans; then back to corn. The narrower strips, usually 30 to 150 feet wide depending on slope steepness and soil type, are replanted on a rotation cycle of two to four years. This layout breaks up the continuous channel that water creates as it runs downslope, forcing it to slow and drop suspended soil particles before reaching the next strip.

The practice serves two critical functions: erosion control and soil conservation. On sloping ground, a single continuous crop acts like a runway for water during heavy rain. The root structure and residue of the previous crop in an alternate strip act as a filter and barrier, reducing water velocity and allowing sediment to settle. Fields with slopes between 2 and 8 percent respond best to strip cropping; gentler ground often does not justify the layout complexity, while steeper ground may require terracing instead.

Field setup and crop selection

The strips themselves must be wide enough for standard farm machinery to operate efficiently. A combine harvester or tractor with typical 10-foot working widths needs lanes at least 40 feet across, though wider strips reduce passes and fuel use. The crops chosen matter: legumes like clover or alfalfa alternate with grains or row crops. The legume strip adds nitrogen to soil while its dense root network holds earth in place; the grain or row crop draws down that nitrogen, creating a biological cycle that reduces fertilizer need while maintaining strip stability.

Contour strip cropping follows the natural hillside elevation lines, creating a subtle stepped appearance when viewed from above. Field strip cropping runs strips at a consistent compass direction regardless of slope, typically east-west, and is more common on gentler terrain or where machinery routing is simpler than contouring requires. The choice depends on slope degree, machinery size, and labor availability for the more complex contour layout.

Adoption peaked in the mid-20th century as a low-cost soil conservation tool on tenant-farmed hillside land. Modern conservation programs in regions with significant runoff still encourage or subsidize strip cropping, particularly where gully erosion or sediment runoff threatens water quality downstream. The practice remains effective but labor-intensive compared to minimum-till or no-till systems that have become standard on larger, flatter operations in recent decades.