minimizing soil erosion

Stabilizing the bank.  Theory into practice.

There is just a bank of solid, dry clay, with a scattering of loose lumps of soil over the surface.  Just walking on the surface causes mini landslides so I can only imagine what would happen if there was a torrential downpour.

Before the work started, the slope was much steeper but solidly held together with a strong network of interwoven roots from trees, bushes and undergrowth.  Additionally, the vegetation provided a covering blanket, gently breaking the fall of hurtling raindrops, cushioning their impact and minimising their destructive action on the surface of the soil.  By the time the water reached the soil it was either as a fine mist of slowly trickling down the stems and trunks of plants in a gentle manner, giving the soil time to soak it in.

This I needed to replicate quickly.

The mini terraces provide plentiful flat areas which will stop the flow of water from becoming too large.  If a trickle starts to flow it will have be slowed or stopped at each terrace, allowing it to be absorbed by the earth.  LIttle landslides will be halted before they gather speed and weight.  They also provide places for autumn leaves to gather and wild seeds to germinate

To encourage the network of roots immediately I have planted broad beans, which are normally planted in autumn.  They will germinate quickly and begin to hold the soil together, the shoots will rise, providing the start of a cushioning layer of vegetation.  In addition, they are legumes, the one family of plants that take nitrogen from the air and transforms it into nodules on their roots, available for soil microbes and eventually other plants to use.  Nitrogen is needed by all plants to produce chlorophyll (the green) and is an essential nutrient for plant life.  I have also planted mustard, cheap and easily cast over the ground, it’ll die off in the winter, but not before sprouting a decent root network and some greenery.  All good news for reestablishing a humus layer for future plants to root into.

There was also that bag of seeds that has been hanging in the van for the last year, getting heavier and heavier.  All the seeds I have collected from hedgerows and gardens around Britain and France.  In a moment of abandon they too all got sown on this bank, so who knows what it’ll look like in a few years time.

Immediately after sowing the seeds, I covered the whole area with a decent layer of partially composted weedy clippings.  The easiest thing to hand and another contribution to soil regeneration.  It will also provide a cushioning effect for any rain that falls before the plants have time to get going.  

Then. as a protection for it all a three to four inch layer of straw. This is the final layer for this side of winter, though there is an additional bale of straw (a big round one) at the ready, should gaps appear, or the wind become strong enough to blow away what is already there.  Amazingly, it all seems to hold together really well and now that there has been some gentle rain, it shouldn’t be going anywhere.

verdant green self protecting slope

bare, erosion ready earthworks in need of protection

mini terracing immediately stop the tiny landslides from getting bigger

plant roots will help stabilize the soil and the compost mulch will
cushion the falling rain

a decent layer of straw to keep it all together, regulate the  humidity of
the soil and keep of the drying rays of the sun

A week later as I write this post, there has been a torrential downpour with no obvious consequences, the mustard has sprouted and is showing green through the thinner areas of straw and along the bare lower slopes and all the wild plants that I put aside have been tucked back in and are looking fine.