When using Vetiver on a sloped area, usually intercropping (growing of crops between Vetiver fixtures) is recommended between hedges of 5m apart for maximum cropping space versus hedge silt capture effectiveness.
Demonstrated above is a Vetiver nursery planting between permanent hedgerows, 3 rows of Vetiver clumps for propagation purposes. One can see how any soil disturbance between the hedgerows would be trapped by the permanent fixtures and this technique could be extrapolated to other growing sites (see below picture). Present here are permanent hedgerow edges to prevent running grasses from entering the nursery area and may not be required elsewhere.
Example of cow intercropping (source: Pablo Ruiz Lavalle):