Wednesday, March 11, 2020

Stacking Functions With Trenches

"Stacking Functions" is used in Permaculture to mean that every element in the design performs more than one function. The ideal is to have each element perform as many functions as possible.

One recent example of stacking functions at our farm:

We got some trenches dug for harvesting rain water. Each one was about 30' long, 3' wide and 3' deep. We filled them up with various kinds of bio-mass -- coconut husks, banana trunks, palm shavings, thorny plants, some manure to inoculate the soil with micro-organisms. Adding bio-mass to the trenches increases the absorption of the soil; exposed soil gets parched and can't absorb much rain water.

As we were wondering how we can "stack functions" using these trenches, we discovered three ways of doing so.

1. Growing area for tubers:
Locally grown betel-nut-leaf tuber needs a 3' deep pit, since each one can grow into a whopping 5 kg. Our trenches thus offered the perfect place to grow these tubers. The bio-mass in the trenches were decomposing for three months when we planted the sprouted tubers. They were planted when the monsoon season had just begun, in July. The trenches harvested the monsoon rains, growing these tubers. We had the (aggressive) tuber-vines climb on a make-shift trellis made by erecting huge dead branches. Last week we harvested 12 kg of tubers. It was very gratifying to realize that we never had watered them;  all we did was to plant them at the right time in the right place. This tuber is starchy like any other; it has a more complex flavor than potato. They can be stored up to one year. Local people have taught us a few ways of cooking these. We look forward to growing them again this year.



2. Trellis and Wind Break:
We had put up a make-shift trellis adjoining the rainwater-harvesting-tuber trenches. We wanted to grow some fast-growing trees that would serve this purpose in the years to come and also provide a wind break. We planted Gliricidia sepium to help with both these objectives. The cuttings were thick and fat and at least 4' long. Even though we never watered them, they are thriving beautifully. Thanks to the work done by the trenches. By next season they will be ready to host the betel-nut-tuber vine.

3. Slow-decompostion of thorny trees:
We have a lot of thorny Acacia spp. trees. We started clearing one patch and piled all the thorny branches and trunks into the nearby RWH trench. This mound of thorns piled in the trench is well above ground now. Once the termites take over it will slowly collapse and add fertility to the trench. We will plant trees close to this trench in the next season.






Here I have documented another way of using thorny plants.

- Hema