Trees, Mulch, & Water Infiltration
We looked hard at the topographical maps as we were designing the orchard rows here at AOOA. It's a steep, compacted, relatively wet site, so we knew it would be a challenge to manage the water. Left to its own devices, water travels straight downhill, picking up speed (and soil particles!) as it goes. We laid out our rows so that they tend to draw water away from the wetter spots, and towards the drier spots. On such a variable landscape, though, sometimes the best we can do is slow the water down, spread it out, and give it time to sink into the ground.
All of our tree rows have thick wood chip mulch, which helps keep the soil moist underneath. The chips act like little speed bumps, and can help the water infiltrate. (Have you ever tried to water a neglected houseplant? Dry soil doesn't absorb water as quickly as moist soil). The mulch also protects the roots of our trees and the various bugs and fungi that also contribute to soil health. In short, we have these rows of living sponges going across our hillsides, collecting water as it goes.
We don't catch all the water, of course, and that's OK. You can have too much of a good thing! But the more we slow it down, the more chances it has to play a part in producing the tomatoes, raspberries, or sheep's milk popsicle you will find at the Farm Stand this season.
This video shows the path that water runoff takes from the stable yard down to the low edge of the property and demonstrates how the design and management of our rows keep soil in place and allows water a chance to infiltrate rather than running off and causing erosion.
The image above shows a row of blueberries with thick wood chip mulch to suppress weeds and store moisture. The left side is the uphill side. You can see where water has infiltrated in this row.
This is the row of juneberries near the vegetable garden. The left side of the picture is the uphill side. You can see how water has run off and is stored by the wood chips, even though there is no surface water at the moment. This is one way we reduce our reliance on irrigation.