Yesterday, I mentioned swales and terracing for water control. These landscape features often used in permaculture design manage water flow. By preventing water run-off, they can also aid in reducing erosion. But in addition to these earthworks, soil stabilisation on a slope also involves thinking carefully about planting.
In permaculture, earthworks and planting cannot be divorced from one another. They must be considered at the same time. In soil stabilisation on a slope, it is essential not only to consider how the flow of water can be managed through earthworks, but also how it is altered by planting. And also, how plants can be used to keep soil in place.
Deep rooted plants and trees are often beneficial in slope stabilisation. They are anchors that can prevent land-slips. They can help in drawing water deeper into the soil, and catching and storing water in the landscape.
But it is also important to include shallow-rooted plants too. Shallow and moderately shallow rooted ground cover plants are crucial for stabilising and retaining the upper layers of the topsoil, and shielding the soil. Bare ground should be kept to a minimum – and that is especially crucial on a slope. These ground cover plants, therefore, can be even more important in the design than the deeper-rooted anchor plants mentioned above.
Of course, when choosing plants for a sloping site, as in any other design, it is important to choose options suited to the conditions. Think about the orientation of the slope and how much sun it receives. Think about the prevailing wind direction, the precipitation levels, and of course the soil type and conditions.
There is no ‘one size fits all’ solution for a sloping site. But whatever you choose to plant – think about their requirements and their root forms and habits of growth. Soil stabilisation should be one of your key considerations.
If you would like earthwork and/or plant suggestions for your sloping site, please do get in touch.