Erosion in the garden

Autumn is well underway and the crops are almost all harvested for the year. Before the fields are fully put to bed under a blanket of snow, it’s worth considering what will be done to protect the soil. Each year, 20 million hectares of land are rendered unusable by erosion (see Planetoscope  for global statistics in real time: www.planetoscope.com ).  Given that the formation of a centimeter of soil can take thousands of years, the process of erosion – when considered on a human scale - can be seen as almost irreversible.

Bare soil is very sensitive to the vagaries of nature. From the perspective of the earth, raindrops are like cannonballs crashing into your garden.  When a single raindrop falls at full speed, one of two things happen: either it hits a leaf, twig or other garden waste and is dissipated, flowing gently to the ground; or it smashes directly onto the earth. If it hits the ground directly, it can do a lot of damage to both the structure and fertility of your soil.

Healthy soil is not uniform.  Rather, it is composed of aggregates – conglomerations of soil particles of varying sizes held together with plenty of space for air and water between them.  When a water droplet crashes into an aggregate, the small particles are separated from each other and spread around – a phenomenon called the "Splash" effect.  This can result in areas of mucky ​smearing or, more commonly, the formation of a hard, impermeable crust. Additionally, if your field or garden is on a grade, the loose particles will then be washed away, eroding the fertile top layer of your soil.

So how to avoid this? There are many ways to put natural umbrellas up over your soil:

• Plant cover crops such as clover, buckwheat or oats in bare areas – especially in preparation for winter
• Intercrop quick-growing vegetables such as radishes or salad mix around longer-season crops such as tomatoes or peppers
• Use permaculture principles to establish perennial ground covers
• Apply mulch year-round
• Knock down dead plant residue but don’t remove it from the garden in the fall – even dead stalks laying on the garden will help decrease erosion and the impact of hard rains

The Splash effect is particularly prevalent in late fall and early spring when not much is growing. If the snow is not yet covering your garden, take an hour this fall to establish some cover and help protect your garden soil for next year and years to come!

 

Photo: soilerosion.net licensed under Creative Commons License

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