The single biggest challenge we face here at Tanglefoot Farm is soil restoration. From the Oklahoma Soil Survey I learned that our property is considered highly eroded Nash-Lucien complex (sandy loam to sandy clay) on slopes of 5-12 percent. Water availability in this type of soil is low to moderate. Hardpan and claypan are common, usually at about 18 inches from surface, resulting in droughty soil in hot weather, and water-logged soil in the Spring and Fall.
What all that means is that we have really crappy soil that is ridiculously hard to dig in most of the time. When it rains, water just races down the hill and off the property. Because of grading for the house, we have some areas of exposed claypan and hardpan covered in a few inches of sand, resulting in a lot of mud and standing water.
Obviously, this is not ideal conditions to start a farm on. But it’s what we’ve got, and I’m committed to restoring it to arable land. It’s just gonna take a few years.
Obtain a Yield
One of the principles of Permaculture is to obtain a yield. You want something to show for the hard work. To this end, I picked a spot on the least-crappy soil we have to put in an annual vegetable garden. It’s a little bit loamier than most, with a teensy little bit more nitrogen than the rest of the lot.
I planted a cover crop of clover, buckwheat, winter rye and Daikon radishes in the garden plot to add nitrogen to the soil and break up the hardpan. Sadly, it got really cold really early, so the cover crop is growing very slowly. I’ll resow in early February, then till it all under before planting the garden in April. While tilling is not ideal, sometimes it’s a necessary evil. In this case, the good outweighs the bad, because the soil desperately needs organic matter. Once the veggies are in, mulch will keep the soil from drying out and blowing away.
The Real Work of Soil Restoration
In the meantime, the real work for the rest of the property is already under way. I addressed several water issues so that the good soil we build stays put rather than washing away. Small check-dams slow runoff at the front of our property. Further, these little dams also catch dirt and silt, and the eroded ditch that existed there last Spring is already filled in. As a temporary measure, we put river rock under the front gutter downspouts to stop the soil erosion on the hill. In the future the downspouts will drain into the irrigation system for the fruit trees.
Our next step is to deal with the hardpan that underlies this entire property. Almost everything I’ve read says to break it up with a backhoe. I’d rather not. A backhoe was used when our septic was put in, and left claypan all over the place. So my yard is super-rocky on that side now, and it’s made water even more of an issue. So no heavy equipment.
The less aggressive solution we decided to go with was “Gravel Plugs” This is a modification of an idea I found at MDVaden.com. It’s pretty straight-forward. We used an augur to drill holes about 2 feet apart in the areas that needs improving, then fill the holes up with with gravel and top with compost. The holes will allow water, nutrients and plant roots to get under the hardpan, and eventually help break it up. Water also drains into the holes so the back yard isn’t such a muddy mess any more. This has absolute cured the water-logging issue behind out house, and we even have grass growing in now!
Continuing Efforts for Soil Restoration
Compost, along with other regenerative measures will play a big role in our soil restoration efforts, because organic matter is about the only thing you can add to clay soils to improve them. Sand mixed with clay will not loosen the soil, it turns it into cement. Some folks advocate adding gypsum to the soil to break up clay, but this causes the soil to become alkaline. And the cure for alkaline soil is, you guessed it, compost. In addition to the compost piles, I started a few vermicompost bins to get some really high-quality soil to add to the garden. Worm poop is a gardener’s gold. In the Spring, we’ll get chickens, who will also have their role to play in regenerating fertility.
Planting the Prairie
The back half of of our property is a mini-savannah. It’s prairie grasses and forbs with a few pioneer trees like Black Locust and Redbuds. Come Spring, I’ll have that area scalped, then lightly till it before planting a Prairie seed mix. In addition to wildflowers and native grasses this mix includes nitrogen fixing plants such as buckwheat, hairy, vetch, and prairie clover. The addition of some tap-root plants like Daikon radish and rapeseed can help break up the compacted soil and hardpan. We’ll seed every Spring and Fall, and nature can do the work of improving the soils there over the next few years. Once the soil tests decently, that area will be planted with fruiting trees and shrubs, while still offering wildlife habitat.
Instead of just wildflowers, we ended up getting involved in a program called “Farm to Foodbank,” and planted a Milpa field. Milpa is a mix of edible nitrogen fixers such as beans and peas, along with lots of brassiccas like collards and mustard, squash, cucumbers, and wildflowers. The seed was provided to us for free by Green Cover Seed, and the local 4-H helped with harvesting. So we were able to begin improving the soil, and give back to the community as well. Definitely a win-win!