Are tropical earthworks worth it?

[u/capitanUsopp]

My grandfather recently passed away, and we deciding to maintain his land as a food forest in his honor.

I see a lot of content on rainwater harvesting and earthworks for permaculture. And im really interested on trying it out. The thing is that most of this content is for dryland, my grandpa's land is a slanted humid tropical forest.

I imagine that water harvesting here would cause mold issue and too much water retention could cause landslides.

What should i do?

Im going next sunday to survey the area

[u/mokunuimoo]

In the humid tropics, where there is plenty of water, earthworks are for slowing down water so it’s not eroding the land or removing nutrients. You still want to sink as much as possible and store it in ponds and vegetation of course, but handling excess becomes more important than capturing every little bit

Any swales or ponds you build WILL overflow so that overflow has to be planned for.

[u/Nellasofdoriath → u/mokunuimoo]

I live in a temperate rainforest area, water can erode if it moves quickly, it also takes energy for us to clean and move and store water unless it is.done passively. Drains should be very gentle, aroumd.1%

[u/Varro-Reborn → u/mokunuimoo]

For maintaining surface moisture, slowing water, reclaiming nutrients, crop diversity, and directing the flow of water.

We get 55 inches of rain here a year in West Virginia and putting long ponds on hillsides is considered a bit crazy. I've had to think about ways to justify it to people. 😂

Our land has almost no top soil on the slopes, so we have surface evaporation that leads to serious cracking.

I've found long but shallow wildlife ponds (more like long tiny dams on slope) completely removes that problem near the pond. So we incorporate them into plots that generally remain in production year round. Mostly plots that grow winter wheat followed by bush or pole beans.

[u/Bad_Baby_Bird]

Is there some sort of permaculture school near by in your area? What general area are you located? Even a school within an 8 hour drive of you would have some better local knowledge. I agree a lot of the permaculture content on youtube is all dry-desert related. Also, Im sorry for the loss of your grandfather! What an amazing gift he has passed on to you.

[u/LeadershipLegal5144 → u/Bad_Baby_Bird]

it's a good instinct to be cautious. swales on a slope in the tropics can go wrong fast if you're just copying what works in arizona, you're right to worry about landslides and fungal issues

instead of holding water on the slope, focus on slowing it down and spreading it out without letting it pool. think more like leaky debris dams and vetiver grass strips across the contour, they act like a living rebar and filter the flow. you could also dig some small level basins upslope of your trees but make sure they have a gentle overflow path, basically tiny paddies that drain slowly

mold is more of a pruning and airflow problem so don't let that scare you off the earthworks entirely. your grandad's land being a food forest already gives you a huge head start, the canopy and root systems are your best engineers

[u/Koala_eiO → u/LeadershipLegal5144]

Regarding your second paragraph: why do all that? A tropical area does not need earthworks to hold more water, it has enough rainfall.

[u/Humble_Ladder → u/Koala_eiO]

Yeah, my first thought on the original post, "why would you start changing things before you understand what you've got?"

[u/pVom → u/Koala_eiO]

Prevent erosion and nutrient loss from water moving too fast

[u/andaugb]

Chinampas are a great earthwork strategy for the humid tropics.

[u/haikusbot → u/andaugb]

Chinampas are a

Great earthwork strategy for

The humid tropics.

- andaugb

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[u/paratethys]

What should i do?

Observe.

Ideally for at least a year.

Whether or not earthworks will improve a particular site depends on what that site needs. Terracing type earthworks can be a huge improvement for convenient human access on any steep slope... but your granddad was already managing his land in the way that worked for him, so start by continuing the management he was doing and deviate from that only when you have a good reason to.

[u/did_i_or_didnt_i]

I kept European worms for composting in Canada. They’re technically invasive in here so they only live in a basement in a container. Make sure not to introduce any invasive species outside because they will throw off your natural balance.

I do think they’re a good quick method to deal with food scraps and get compost. If we compost outside it’s a lot of work to keep the raccoons off

[u/Koala_eiO]

What should i do?

Nothing for now. It's pointless to apply other people's solutions to problems you don't have.

Landslides are caused by lack of roots, lack of ground cover, and erosion.

[u/OMGLOL1986]

Plant a food forest with all the trees you like, and while the plants are very young, cover the entire landscape with sweet potatoes so that weeds do not grow. You will have more sweet potatoes than you want for a couple years, but your trees and shrubs, etc. will be very happy with your efforts.

Don’t worry too much about harvesting water. The plants are pretty good about that. Plant the wet stuff where it gets wet and the dryer stuff where it stays dryer.

[u/Sweet-Trees-Hawaii]

Would help to know where it is.

It sounds like you don't need water retention - probably the opposite. Here in Hawaii we need more drainage than water retention. Rains almost daily...

Use the permaculture method for the conditions you have.

[u/bwainfweeze → u/Sweet-Trees-Hawaii]

Unless you’re growing wapato or taro…

[u/Sweet-Trees-Hawaii → u/bwainfweeze]

Yes, but even then dryland taro doesn't need soggy ground.

[u/Latitude37]

Well designed earthworks will slow water movement across the landscape, reducing erosion and filling underground aquifers. This will make the land more resilient in drought conditions, and less susceptible to flood damage. The Permaculture Design Manual has some really useful information on tropical design methods.

For a good case study, these two videos from Geoff Lawton's Zaytuna farm in subtropical NSW show how good design works in both extremes. From the terrible drought of 2020-2022:

https://youtu.be/2kM8G0zDoBo?si=unbsTeRtZtSoCCw6

To the floods that followed:

https://youtu.be/XIn00ihb3hU?si=Cn0p3MHv78gCYGpK

[u/ForagersLegacy]

Please for the love of god learn about edible native plants in that area of the world before planting anything.

[u/Micky_G42]

A coffee farm I worked at in Costa Rica, before they implemented earthworks across their hillsides, had only one natural water spring. Thirty years of reforestation and multiple linear kilometers of level curves later, they now have four natural springs on their property that all feed into the creek at the bottom of the valley. It helped the native trees, ferns, and flowering shrubs grow back on their land, all while still harvesting coffee under the shade. For them it was definitely worth it

[u/Plane-Ad-9360]

Pour suivre, je cree un logiciel ce sujet en ce moment