Rivenrock Gardens Cactus Blog… go to www.rivenrock.com for edible cactus

   Some of our best soil is in the little arroyo where we grow many of our plants.  The nutrient-rich clay particles tend to unravel from the rock strata, and work their way into the arroyo where the rich gravelly soil provides the perfect blend of nutrients and moisture conditions.

   But life doesn’t always lay everything you want at your feet, sometimes you need to go up that hill and work.

   So, I build terraces on the hillside. The native soil on the hill is still very good for cactus. I just need to make it a bit better, and get water to it. there is a danger however in working hilly land.  Newly disturbed soil is very prone to washing or blowing away… and this risk is increased exponentially with the degree of slope involved. For this reason, it is good to make a series of flat areas on the hillside, these are referred to as terraces.

   Each terrace will provide a level and firm area that I will be able to get equipment onto to maintain the ground, add amendments, run irrigation and harvest from comfortably and safely.

   The terrace will also help reduce soil and moisture loss. Ideally, when it rains the terraces will hold the water allowing it to infiltrate into the soil, adding to the groundwater, and making up for some of what I pull from the ground with the well pump.  Under the best conditions, this hillside should have no water run off.

   There are many ways to build terraces, and I have used several of them. We’ve built terraces using chicken wire and re-bar to hold the soil, we’ve also used galvanized metal as backing, and we’ve  made terraces using tens of tons of waste concrete pieces from demo projects. But now as I work my way higher up the hill, carting tons of concrete uphill by hand is seeming like less a viable option. So now I am building the terraces with themselves. Yes, the ground alone will provide the backing for these structures.

   Building in such a way is slower than using concrete or other backing material. You must allow the soil to heal after disturbance and placement… you should allow the local grasses to dig their roots into the terrace to help stabilize it. It is best done a bit at a time, over the course of a few years. This will give you the time to till the soil yearly, letting the grasses grow thick and strong locking the soil into place, then you come and till along the growing spots, leaving the structural areas of the terrace undisturbed. Year by year, this tiling can be done, allowing the soil to become more suitable to plant growth, until the time comes that you wish to plant. I think five years is a good time to consider proper from initial building, to the final planting of the crops. If necessary of course, a person could plant sooner, but that would be best done with many inputs to improve the soil. Since I am working so high up the hill, away from inputs, I prefer to work slow, with one tilling yearly as the soil slowly grows healthier, and one day, when I need the growing ground, we can easily plant and increase our harvest.

   This is one terrace we cut into the hill some four years ago.  We let the native grasses grow thick on this soil, and we till a strip down the center every spring. This will improve the soil where we will plant a row of cactus (someday). The grasses getting tilled in will slowly rot and release humic acid. The acids will etch the native shale rock, helping to break them down.  I will then weed-whack the grasses on both sides in such a way that the grasses lay down over the exposed and vulnerable soil, acting as a protective mulch to prevent the wind from ripping along the hillside carrying away the soil I work so hard to build up. Year by year this soil becomes more amenable to planting…. I could plant cactus into this soil at any time I need the extra space.

terrace building

      This is the same terrace with the weeds cut down to lay a protective blanket over the open soil. This soil will now sit through the summer, the weeds slowly rotting into the ground and some laying over the top. When the rains come again in the winter, the weeds will quickly grow in this improved soil, and we will repeat the process.

terrace building

   This is the next terrace up the hill.

It is important that the native plants, and later introduced plants be allowed to fully colonize the soil with their roots. the plants are a large part of what keeps such a soil  together.

  Terraces much be maintained…. there are many places in the world where the young people have walked from their remote villages to make their fortunes in the cities, and now the world of terraces is full of old folks who cannot properly maintain the terraces that in some cases might be thousands of years  old.

My thinking is that in this age of rising population, and scarcer resources, small hand-built terraces will again be seen as a viable agricultural alternative.