Chapter 17

Soil Management for Field Crops

Strip Cropping

Strip cropping is defined as the production of two or more crops within the same field in strips wide enough that each can be managed independently by existing machinery; yet narrow enough that the strip components can interact. Strips are sized to accommodate multiple or full-width passes with tilling, seeding, harvesting, or other equipment and are usually of equal width. Strip boundaries should run parallel to each other and as close to the contour as practical. Additional consideration should be given to the prevailing direction of erosive winds when wind erosion is a resource concern. In arid and semiarid regions, strips may be placed perpendicular to the prevailing wind direction for wind erosion control. The most effective strip-cropping systems include perennial grasses and legumes that alternate with grain and row crops. Each crop strip is rotated annually.

Types of Strip Cropping

There are four general types of strip cropping.

Contour Strip Cropping

Contour strip cropping is a sustainable way of farming where farmers plant crops across or perpendicular to slopes to follow the contours of a slope of a field. This arrangement of plants breaks up the flow of water and makes it harder for soil erosion to occur. Plowing and planting across slope contours create man-made water breaks that not only allows enough time for the water to enter the soil, but also to settles the topsoil without washing it down the slope. On slopes with no contours, water runs off quickly without the soil properly absorbing it and carrying the top fertile soil with it, therefore, leaving a non-fertile land up the slope.

Considerations for Contour Farming. In large, steeply sloping fields, it may take several BMPs to tackle the soil challenges that exist there. Contouring will reduce tillage and sheet erosion, but erosion control structures (e.g., grassed waterways) may be required for channelized flow if draws and washouts (i.e., large rills and gullies) are found in the field. In the recent past, design and layout of contour farming systems—especially strip cropping – required tools such as contour gauges or levels.

Field Strip Cropping

It is modified form of contour strip cropping, in which crop strips are laid parallel, across the land slope, but not always exactly on the contour; may be changed depending on the land situation. This type of strip cropping is suitably used where the topography is either too irregular or undulating, as they make accurate layout of contour strip cropping, impractical. Typically, lines are of the same width.

Buffer Strip Cropping

In buffer strip cropping, the strips of grasses or legume crops are laid between contour strip crops in regular rotation. They are not necessarily of the same width and distance, which depends on the relief specifics. Buffers strips are usually narrower than the cultivated strips. Their purpose is exactly what the name tells–they protect soils and cash crops serving as buffers.

Wind Strip Cropping

In wind strip cropping system, the strip crops of uniform width are laid at right angles to the direction of prevailing winds, without regard of the contour. The main objective of this system is to control the wind erosion rather water erosion. This cropping system is recommended for level or nearly level topography, where wind erosion is more effective.

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