Alley cropping in a hillside terrace system

Alley cropping in a hillside terrace system

Summary

The project began by using a laser level and my neighbor, a professional excavator, to mark a series of parallel contour lines progressing up the hillside approximately every 20′.  Then using a Bobcat Track Hoe, Rusty began the day of digging and moving earth.  The approach that he developed for the project involved scooping and loosening the dirt in front of him with his back hoe and then spreading some of the cut earth downhill.  He could then push through with the blade of his plow and level the area.  In this manner he was always working in front of him and driving over the newly created terrace, allowing his equipment to remain level and secure during operation.  While effective for him and seemingly making good time (we created 5 terraces each about 150-200′ long by 5-7′ wide in about six hours), this process resulted in several challenges down the road.  In the past I have hand dug many smaller terraces, allowing myself the opportunity to carefully place topsoil and avoid compacting the newly created bed.  Our new approach with the excavator had the opposite effect for several reasons.  For one I wanted wider beds which necessitated cutting deeper into the ground on the uphill side, creating a situation where at some points the back side of the terrace was almost 3 feet below grade and partially cut into subsoil or even bedrock.  Not the most delicate machine or operator, the excavator was not able to strategically place the topsoil and it was all incorporated into the berm and lower portion of the terrace bed.  To further worsen the conditions of the bed, it was repeatedly driven over with a massive piece of equipment throughout the creation process.  Despite these unforeseen consequences beautiful earth-bermed terraces emerged.

Getting a later start on the project than our timeline supposed we would, we were not able to smother the existing vegetation between the terraces to make way for planting as we had intended.  Instead we hand turned the areas above each terrace to be studied in order to prepare them for the planting of our experimental fertility patches.  This was carried out immediately after excavation so that we could quickly establish plants and stabilize the ground above and below the terraces.  We were able to acquire seed for many of the varieties, starts of some, and transplants of others. We sowed one test plot in stinging nettle, white clover, and blue false indigo, and planted large root cuttings of comfrey.  In the second patch we sowed dandelion, yarrow, switch grass, and white clover, and we planted more root cuttings of comfrey and transplanted a half dozen goumi bushes.  The third plot we left in existing ground cover (mostly brambles, grasses, iron weed, and purple knot weed). Lacking ideal irrigation, we hand watered the site three times over the first week and then let nature take its course.  It rained several times over the next few weeks helping the comfrey and goumi to take hold, but not providing the right condition for anything else to germinate except for weeds from the existing seed bed.  To remedy the situation, we hoed between and above the comfrey plants and goumi bushes and sowed again, but still no luck.  Through local community networks we located several patches of established plants that we could dig.  We transplanted stinging nettle, yarrow, and horsetail, mulched them and again watered repetitively.  The nettle and the yarrow took well but the horsetail quickly withered (I don’t think it is suited for our site conditions and may need to be grown in a wetter environment and cut and carried for mulch).  Still struggling to establish the other plants we took the remaining seed and started plants in pots in our greenhouse.  We now have the indigo and switch grass established and ready to plant in the spring.  The dandelion we will attempt to broadcast again and hope that some of the seed from last year germinates.  

Off to a slow start with establishment, even the plants that did take seemed to need some time to get comfortable before they were ready to be cut and harvested for mulch.  Because of these hiccups, we decided to push back the experiment for one year and focus on improving the growing area (the compacted subsoil on the terrace beds).  And so a side experiment began. How best to improve compacted subsoil?  We began by double digging three of the five terrace beds including the one in our experiment (our test plots are all contained in one 200′ long terrace and the other terraces were used for further experiments).  We then spread a one-inch-thick layer of aged cow manure across these three terraces and one other.  Next we sowed clover on all the terraces.   We then immediately planted potatoes just below the ground in the two terraces that had been double dug and manured (not the test plot) and spread a two inch layer of hay mulch over top of them.  The other terraces that were not dug were sown in radishes and beets along with the clovers.  The test plot was mulched with straw on top of the manure.

The radishes, beets, and clover germinated and flourished and we let them grow throughout the year.  We harvested a nice crop of potatoes from the double dug beds and noticed a good soil structure had begun to form and the color had darkened considerably.  All of the beds (except the test plot) were then rototilled and planted to a winter kill cover of radishes, crimson clover, cow pea, beans, and grain.  This flourished until killed in late January by severe cold.  In the spring we will discover the extent of the improvements to the soil and which method benefitted it the most.

Having received a bit of treatment (double dug, manured, planted to clover and mulched, we then took soil samples from each plot in the test terrace to measure the new baseline.  We also did this for the soil in the two experimental mulch producing plots and the control.

In the spring we hope to have a soil capable of producing butternut squash and a more established fertile patch from which to cut mulch.  We will establish our remaining plants early and hope they are ready to cut by summer so that we can resume our original timeline.

• Double dug with manure incorporated to break up subsoil
• Excavating Terraces
• Completed Terraces

Objectives/Performance Targets

One observable success is that the terraces have performed wonderfully.  During heavy rains they catch and hold considerable surface runoff, and standing water can be observed across the terrace beds.  Additionally, through hard rains and many freeze and thaw cycles, the terraces and the berms below have remained in perfect condition and appear to be highly stable and long lasting.  

Another success is the establishment of the comfrey, nettles, yarrow, clover, and goumi—all of which have thrived and taken over their target areas quite well.

• Comfrey and nettle polyculture

Accomplishments/Milestones

The delays in our schedule mean that measurement of various important components of the project will have to wait until next year.  As stated above this year’s accomplishments are the establishment of a stable terrace system and the establishment of many key species in the fertility patches.

We did however obtain soil sample to establish a baseline from which we can now measure improvements.

Impacts and Contributions/Outcomes

The terraces and the project at large were a great teaching tool during the permaculture design course at the farm.  Over the seven weekend course, I was able to discuss the project and theories behind it with over 30 participants.  During the summer the project was the topic of many farm tours including a training for interns of a large local organic farm.  The terraces were discussed with the 30 local Americorp Vistas and their supporting non-profit agency members at an annual day of service at the farm.  Furthermore the terraces were a new area for learning and exploration at our summer day camps and the soil building process was examined by over 60 youth.  

The greatest sharing opportunity came at the Ohio Pawpaw Festival where I gave a PowerPoint presentation explaining the theories behind the project as well as the implementation and vision.  This talk was attended by over 70 festival participants.  

I continue to update the project on my facebook page and discussion of the topic is often renewed.  Now I am preparing for this year’s permaculture course where the terraces will again serve as a valuable teaching tool.  

Beyond the impacts on others the terraces have had a great impact on me.  Several of them provide access to old farm apple trees that could formerly only be reached with machete and great determination.  They also weave between bramble patches providing access to berries.  They create a stable and accessible ground from which to manage the areas between them, provide excellent walking and cart trails, and exciting sledding features during the winter.  Based on the performance of these systems, I am planning to terrace the many other hillsides on our property making them more accessible and more productive.

• Soil Building Presentation
• A new trail to the apple tree

Collaborators: