Tuesday, February 1, 2011

Use Garden Debris to Improve Soil and Prevent Erosion

Here in the south, we don’t experience much of an autumn season.  The high temperatures go from mid-90’s to low-80’s and then we start getting dry cool snaps followed by humid warm spells.  Sometime around Christmas, we start to see some leaves fall and plants die back. Then in January, we see more brown outside than green.  So, what most of the country experiences in leaf color change and leaf raking in autumn, we experience in January through March.  Many of our evergreen trees, like Live Oaks and Southern Magnolias drop leaves in the spring when new growth starts.

Composting needs both green material with high nitrogen and brown material with high carbon content.   If you have too much nitrogen, you might get nasty smelling sludge rather than crumbly compost.  On the other hand, lots of carbon just means it probably will not break down as fast as you would like.

So, our time for collecting carbon material for the composters in January through March, just before we start having lots of green grass clippings again.  Since we have so much brown in the winter and so much green the rest of the year, we have started using a separate large trash can to hold all the brown.  Since it doesn’t break down quickly, it is easy to put a few shovels of brown stuff in the compost bin when we need it throughout the year. 

This winter, after composting all year, we still have brown stuff in the large trash can left over and now we have lots of raking and pruning to do, but nowhere to put it.  To make good use of the last winter’s brown stuff, we will use it to stop erosion.   Since it will sit in place for a while before decomposing, we will dump the brown stuff on a bare eroding slope, in a row perpendicular to the slope.  As water runs downhill, the row of dried leaves and clippings will absorb water and top soil, allowing it time to soak into the ground rather than running off it. The brown stuff will slowly compost making for richer soil on the slope.  Richer soil will allow for grasses and shrubs to grow, which will also prevent erosion.  This technique, called a water break, can also be accomplished by laying logs perpendicular to the slope. 

Using yard debris to create a waterbreak is a great way to prevent erosion.  Using what would otherwise be considered waste is a key concept in permaculture.  Another key concept is that each function of the system has multiple uses.  So in this case, a) yard debris is not sent to the landfill, b) when yard debris is laid across a slope it will catch water and prevent erosion, and c) yard debris will compost in place allowing for more plants to take root.  Permaculture is a system that creates cycles of functionality and integration between natural systems.  I think permaculture is a great study in sustainable solutions.


For more information about permaculture, this is my favorite book on the topic. This author not only tells about the concepts, he can tell you details because he has done it.