SALT and Sloping-Land Cover Crops in the Uplands

Combine contour hedgerows with a legume cover between them to hold upland soil on a slope. Sloping Agricultural Land Technology, or SALT, is a Philippine upland farming system built on contour hedgerows that slow runoff and trap soil. A legume cover crop sown between the hedgerow strips covers the bare ground, fixes nitrogen, and stops the alleys eroding between the rows. Together they keep upland soil in place where straight cultivation would let it wash downhill.

This article covers how SALT controls erosion, which cover crops to grow in the alleys, and where vetiver fits on the steepest ground.

What is SALT and how does it hold soil on a slope?

SALT uses contour hedgerows planted across the slope to break the length of the run and slow water before it can carry soil away. By dividing a long slope into short alleys between contour hedgerows, SALT stops runoff building speed and lets water soak in and drop its sediment at each hedgerow line. Over time the soil terraces up behind the hedgerows. It is a low-cost, plant-based way for upland Philippine farmers to crop slopes that would otherwise gully and lose topsoil every wet season.

The hedgerows alone leave bare alley soil between them, which is where a cover crop earns its place.

Which cover crops suit the alleys in a SALT system?

Sow a creeping legume cover such as Pueraria javanica or Centrosema pubescens in the alleys between the hedgerows. A legume cover closes over the bare alley soil, takes the impact of rain off the surface, and fixes nitrogen the upland crop can use. Pueraria javanica (Neustanthus phaseoloides) covers open ground quickly and fixes around 150 kg N per hectare per year on a typical site; sow it at 4 to 6 kg per hectare pure or 2 to 4 kg per hectare in a mix. Centrosema pubescens is a hardy, persistent creeper that holds difficult upland soils and tolerates shade as alley crops grow.

Note: Pueraria javanica is a managed tropical legume, not the invasive kudzu (Pueraria montana).

Keep the cover trained across the alley and off the hedgerows and crop rows, and slash it back when it competes with the upland crop, leaving the slashings as mulch.

Do cover crops alone stop erosion on a slope?

A legume cover reduces surface erosion but does not replace the contour hedgerows on a steep slope. The cover protects the soil surface from raindrop impact and slows sheet flow, but on a long or steep slope you still need the hedgerow structure to break the run and trap sediment. Cover crop and hedgerow do different jobs: the cover protects the surface, the hedgerow controls the slope length. Use both.

Where does vetiver fit on the steepest ground?

Plant vetiver (Chrysopogon zizanioides) hedgerows on the steepest contours where you need maximum holding power. Vetiver hedgerows can cut erosion by up to 90% and runoff by up to 70% on slopes, and the roots reach 3 to 4 m, which makes a stiff, deep-anchored barrier across the contour. On the steepest SALT lines or on gully-prone ground, vetiver is a stronger hedgerow than softer species. Keep the legume cover in the alleys between the vetiver lines for the nitrogen and surface protection.

FAQ

What cover crop goes between SALT hedgerows? A creeping legume such as Pueraria javanica or Centrosema pubescens. It covers the bare alley soil, protects it from rain, and fixes nitrogen for the upland crop. Pueraria fixes around 150 kg N per hectare per year on a typical site.

Is vetiver better than a cover crop for slope erosion? They do different jobs. Vetiver hedgerows across the contour control the slope length and can cut erosion up to 90%; a legume cover protects the soil surface between the hedgerows and adds nitrogen. Use both on a steep slope.

How much Pueraria seed for an upland alley? Sow 4 to 6 kg per hectare for a pure stand or 2 to 4 kg per hectare in a mix, adjusted for the alley area between hedgerows.

Design your upland cover

Tell us your slope, crop, and whether you run SALT or vetiver hedgerows, and we will recommend an alley cover and seeding rates. Request a quote on WhatsApp at +60 17-237 4058 or through info@kudzuseeds.com.

Sources

• Vetiver hedgerows: erosion down up to 90%, runoff up to 70%, roots 3-4 m (VET1): https://www.sciencedirect.com/science/article/abs/pii/S100162792200066X
• Tropical Forages, Neustanthus phaseoloides (Pueraria javanica): https://www.tropicalforages.info/text/entities/neustanthus_phaseoloides.htm