Strip cropping is growing planned rotations of erosion- resistant and erosion-susceptible crops or fallow on cropland areas in a systematic arrangement of strips across a field.
- Reduce sheet, rill, and wind erosion.
- Minimize the transport of nutrients, sediment, and pesticides in surface waters.
- Increase infiltration and available soil water.
- Improve plant productivity and health.
- Expand wildlife habitat.
- Diminish emissions of airborne particulate matter.
How Does This Practice Work?
Strip cropping is effective since crops are arranged so that a strip of grass or close-growing vegetation is alternated with a clean tilled section or area with less protective cover. The strip widths are typically equal across the field.
On sloping land where sheet and rill erosion are concerns, the strips are laid out on the contour or across the predominate slope. Where wind erosion is a problem, the strips are positioned as close to perpendicular as possible to the predominate erosive wind direction. A minimum of two strips should be included within the conservation planning slope length. Strips of crops susceptible to erosion should be alternated with strips of erosion-resistant vegetation. Crops, forages, specialty crops, or cover crops should be grown in a planned rotation. At least 50 percent of the rotation should be in erosion-resistant vegetation. Erosion susceptible crops should not be included in adjacent strips at the same time during the year. However, two adjacent strips may be in erosion-resistant cover at the same time. The critical slope length for contouring should not be exceeded when designing the strips. To improve cropping system diversity, a crop rotation at least three years in length should be considered including at least three crop species from different plant families.
Strip cropping systems are visually appealing and they enhance the attractiveness of agricultural landscapes. A well-managed strip cropping system could result in higher profitability and greater soil and water conserving potential than many mono-cropping operations.
Where This Practice Applies and Its Limitations
This practice is used on cropland and selected recreation and wildlife areas where field crops are grown. The maximum width of each strip should be determined using current erosion prediction tools, considering both water and wind erosion. The critical slope length for contouring should not be exceeded, and strip widths should be adjusted to multiples of the width of planting equipment. The effects of other on-site runoff and erosion control practices should be considered in strip cropping system design.
Pesticide and fertilizer application periods vary among crops. Since more than one crop is used withing a strip cropping system, the total amount of pesticide or fertilizer applied at a particular time is reduced. This decreases the probability of substantial off-site transport of pesticides or fertilizer as a result of significant rainfall occurring soon after application.
If small grain strips are dispersed among strips containing other vegetation, summer manure application may be possible following small grain harvest. This reduces or eliminates the need for manure addition during other periods when nutrient losses are more likely to occur and when soils may be more susceptible to compaction. A legume may be interseeded into the small grain strips to enhance nitrogen fixation. The nitrogen fertilizer requirements for the row crops which is later rotated into the strip is reduced.
Strip cropping is most effective when used in combination with other nutrient and erosion control practices. No till or reduced till, residue and tillage management are best suited for strip cropping systems since strip position is fixed from year to year. Planting position is easily identified with these tillage systems based on the previous year’s residue and row direction. Contour farming serves to reduces erosion, as runoff accumulates in furrows allowing sedimentation to occur. Cover crops including grasses and legumes may be seeded within selected strips to provide seasonal cover and nutrients for succeeding crops. Wildlife benefits can be enhanced by selecting vegetative species and management practices that improve habitat. Harvesting of vegetation should be delayed until after the nesting season.
Sediment transport can be substantially reduced if small grain or forage strips are present. A strip containing dense vegetation serves as an effective filter for sediment removal from runoff. A dense vegetative strip decreases the susceptibility to erosion through its extensive root system which helps to hold soil in place. The dense vegetative material reduces flow velocity and sediment transport capacity. The backwater occurring upstream from vegetative strips may also cause significant deposition. Vegetative filters work best if runoff enters the strip as sheet flow. Placing small grain or forage strips on hillslopes results in water entering the strip as sheet flow more readily than if the vegetative filters were located only at the bottom of hillslope.
Cost of Implementing the Practice
Strip cropping is one of the least expensive erosion control practices. An investment of labor and fuel is required, and in some instances a change in cropping sequences may be needed. Expenses may also be incurred to establish grasses or legumes in selected strips in a long-term crop rotation.
Operation and Maintenance
Strip boundaries should run parallel to each other and as close to the contour as practical. Strips susceptible to erosion should be alternated down the slope with strips containing erosion-resistant vegetation. Erosion- susceptible areas are usually defined as row crops or fallow with less than 10 percent surface cover and minimal surface roughness when erosion potential is greatest. An erosion-resistant strip typically contains dense grasses and/or legumes, hay, or row crops with surface cover greater than 75 percent during periods of greatest soil loss potential.
A strip-cropping system should not be established on a site longer than the critical slope length unless supported by other erosion control practices. Strips should be designed and established to best facilitate the operation of farm equipment. To avoid point rows, strip widths should allow full width passes of farm implements. If possible, strips should be established perpendicular to fence lines or other barriers.
The crop rotation utilized on strip-cropped fields should be consistent with the farm enterprise and any associated livestock operation. The existing cropping and management system will influence the proportion of row crops, close growing crops, specialty crops, cover crops, or grass/legume forage crops.
Sediment accumulating along strip edges should be smoothed or distributed over the field to maintain practice effectiveness. Sod turn strips should be mowed at least once a year and harvesting of the sod is optional. Farming operations should be conducted parallel to the strip boundaries. To capture and manage soil moisture, crop varieties and crop rotations should be selected to provide sufficient density and cover to intercept and capture blowing snow. The height of vegetation should be maximized to enhance snow trapping potential.
To obtain information on the Conservation Practice Standard described in this article, Stripcropping, Code 585, contact your USDA-NRCS State Office or visit the Field Office Technical Guide online at https://www.nrcs.usda.gov/ and type FOTG in the search field.
Gilley, J.E., L.A. Kramer, R.M. Cruse, and A. Hull. 1997. Sediment Movement Within a Strip Intercropping System. J. Soil & Water Cons. 52: 443-447.
For Further Information
Contact your local soil and water conservation district, USDA-NRCS or Cooperative Extension Service office. To find your local USDA Service Center, visit https://www.nrcs.usda.gov/contact/find-a-service-center.
|John E. Gilley
Editing and Design
NC State University
University of Tennessee
Gilley, J. and K. Wacha. 2023. Strip Cropping. SERA17 Phosphorus Conservation Practices Fact Sheets. https://sera17.wordpress.ncsu.edu/strip-cropping/