How do I avoid the Burning part of slash and burn?

Agricultural Techniques Soil Life
#1

We are just starting an agricultural project in the jungle region of Pucallpa, Peru in South America and unfortunately the government is colluding with squatters and we are at risk of losing the donated land. The land is zoned for agricultural use and since we recently got it we have not been able to develop it yet as we are still designing for it (also currently we’re stuck in the USA due to COVID-19, but have partners in Peru helping us). If the property looks abandoned as it does now, we are at risk of losing losing it so we need to quickly plant some productive species in order to keep it. I want to use sustainable long-term design such as is taught in Permaculture so eventually I want to implement swales, ponds, fruit trees, leguminous nitrogen fixing trees, etc. Now it is over 2 hectors of tall jungle that has been fallow for probably eight years although multiple times my neighbors’ fires have come over and burnt parts of it. Slash and burn is the normal practice here but I am trying to teach our agricultural Peruvian neighbors other practices and how to maintain soil fertility with using sustainable practices such as mulches and in the future other techniques as well possibly including biochar, etc.

Right now the urgency is that we have people that we are paying to cut down the tall jungle but since it is over 10 foot high, there is a ton of biomass on the jungle floor now. I really really want to avoid burning at all as that would represent losing years of available nutrition for the soil, but I’m not sure of the best way to plant trees such as guaba (legume - AKA Inga or icecream bean), coconuts (we have about 10 probably over a meter tall), or other nitrogen fixing ground covers (like perennial peanut / clover) that could grow faster than the native weeds / biomass that was just cut down. I want to leave the biomass, or maybe just move it, so it can rot and basically eventually turn into good soil to not lose 8 years of growth with just a fire. Is it feasible to leave the mulch there without burning or will the undesirables overcome and smother the coconuts and new guabas? 

Can I just for example clear very low to the ground 1 square meter in order to plant a coconut tree, then leave the rest of the cut down stuff around as mulch? I have videos and pictures here with explanations in Spanish in this video (click here). As you can see in the video, the biomass is significant.

Or should I do like a type of alley cropping where we clean very low to the ground like a row of two of 3 m wide by 30 m long? And Plant in that low cleared area?

What legume nitrogen fixing species grow super fast and easy in this tropical climate?

Another complicating factor is that we don’t currently have water on site, September is a dry month, but since we have a place on site that is super close to the water table (could be flooded during the rainy season Dec - Feb) our partners believe they can just dig down a meter or two and find water and can bucket it up to water the plants, although the walk could be about 100m, so not terribly easy.

Can you brainstorm with me to help think of other ideas to keep the biomass in order to maximize our success of maintaining plant nutrition and helping the plants we want to grow outcompete the plants we don’t want to grow? In just a couple weeks the cut down stuff could spring to life possibly. I wonder if we piled up the mass like 50cm high or more if it could grow back…

Any other ideas on how to avoid burning everything? The suggestion from our partner there is to just burn it once (now) and never again… yet I’m not sure about that either. From my limited research burning can burn the weed seeds if it’s complete, yet it also leave room for invasive weeds to spread like crazy too. So either way it seems there’d be a fight with weeds, right? Maybe less of a fight at first if we burn.

I’m concerned if we burn about:

  • Erosion and losing top soil when the heavy rains come (tropical monsoons)
  • killing earthworms
  • eliminating the nitrogen and potassium, and magnesium
  • lowering the organic content of the soil
  • killing the biota / microbiome / good bacteria in the soil
  • controlling the fire from burning neighbors’ yards

Yet burning seems to release some other nutrients too.

#2

You may have trouble convincing people to do the extra labour, but you could dig pits and stuff the biomass into the pits. If you can find some EM bacteria already cultured you can add this to the pit, and if not, cow or other livestock feces slurry works pretty darn good too to start the decomposition process. Fill the top of the pit with the soil you dug out to make a bit of a hill. The hill will shrink down as the biomass decomposes underneath. You could get this done now in the dry season, and then when the rains come the decomposition will happen fairly quickly. I have done this in a subtropical region (Nepal) but not a tropical region, and I am assuming that the decomposition will be even faster there than here. In Nepal, the pre-monsoon filled pits have decomposed mostly by the end of Monsoon. …We used softwood annual weeds mostly as our biomass. If you were to use harder wood it would decompose more slowly. Regardless, you will end up with nutrient rich, awesome soil that is deep. Probably the farmers will appreciate it, as it is my understanding is that slash and burn produces a poor quality soil that can only be used for a short time.

Good luck!

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#3

Ingafoundation.org has good information. If the regrowth is really only about 10 feet high over only 2 hectares if you have several workers with axes, machetes, and pitchforks (or better yet a chainsaw and a chipper / shredder like DR Powertools makes) then it would not be impossible to chop up the vegetation significantly and pile it in windrows. Initially you would plant a row of a locally appropriate variety of Inga trees down the middle of the bare ground between the windrows with leguminous crops like soybeans or cowpeas to each side at the base of the windrows. As the windrows of vegetation start to decompose into mulch, you could plant a row of either Inga trees or, potentially, a slower growing and somewhat more demanding leguminous tree that could however, one day profitably be harvested for timber such as a true Rosewood - provided that there is a local market. Along the sides of this row of trees you would once again plant rows of leguminous crops. By the time this second crop is harvested at least two seasons have passed, the first row of Inga trees is getting good sized and the second row of trees is established. Significant nitrogen should have been Incorporated into the soil from the various legumes by this point, and you could probably either begin a diverse crop rotation or plant your permaculture crops

#4

Hi Dave

I absolutely agree on all your concerns about burning.
I‘m no fan of paying people to cut down trees without a plan as well.
Wouldn’t it be enough to fence the area? In uruguay, where I worked, you just had to put a fence around your area so everybody could see it is private property. How is the legal situation about this in peru?
I highly recommend you Check out and contact the chaikuni institute. They promote a forest converting system without burning using permaculture principles and are situated near Iquitos. So you are somehow neighbors. They really love their forests and treat them with respect while converting it to a food forest. They are local experts with experience and their method can be used anytime in any season and no nutrients are lost.


Best wishes J.

1 Like
#5

Yes concur with all the above - let the biomas do the work! Chop and drop - use some of the biomas to make compost, as mentioned bio-fertilizers/home-made EM will speed up the process, and mulch the rest. Personally I’d make compost piles rather than pits just because it’s less work. Cutting biomas before flowering will harvest more nutrients; allowing to flower will be good for pollinators; allowing to seed will promote regeneration - choose what is appropriate depending on what labour is available, and when. Do you have hand-operated chaff cutters? They’re great at reducing biomas to chips that will compost rapidly - we use them a lot in Nepal for making mulch/compost/biogas as well as for livestock fodder. Finally, nature will always try to re-colonise to forest, so when designing your plot maybe tropical forest-garden systems will be lower input in the long run. light management is the key to balance diversity with succession.

#6

Sorry for the bad link for the video, hopefully this one works: https://vimeo.com/452009759/34a938c4b0

No chippers exist here, but that would be ideal. I have a friend that might import one eventually or try to make one, but that might be a couple years, we’ll see.

Leslie, I like the dig and fill idea, but I’ll probably wait till I can go back to Peru and I’ll use that idea but with swales on contour. It will be intensive labor and require direct management to make sure the swales are on contour.

John, I’m going to look into Ingafoundation.org, thanks so much for that! Sounds great!

Jorg, I like the look of the Chaikuni Institute, I plan to communicate with them to get help also. Thanks for that connection! Also, fencing the area might help, but besides being too expensive for our current budget it would still need to be planted with productive species as it’s zoned agriculturally. The ideal long term is maybe a living fence + permaculture paradise + someone staying there, but as I understand it the first most urgent step is to clear it and plant it so it doesn’t look abandoned. It could have a fence and still look abandoned if I didn’t plant and clear also.

Chris, good observation about the effects of cutting down stuff at different stages, that’s insightful. I just told them to cut down the undesirables and honestly since I’m not there I have no idea what stage everything is in! :slight_smile: I’ve never seen nor heard of chaff cutters, but I made a note of it and will look for them when I get back. I asked a local contact also to seek them out.

Thanks for the help everybody. The crazy thing is that due to strong winds, some of our property was already partially burned anyway as another neighbor was burning their field :frowning: But I think or hope that most of it wasn’t burned.

Any other follow up thoughts?

#7

Hi Dave

I recommend planting nitrogen fixing trees (NFT) And other multi purposes trees like Moringa spp. Leave any useful trees like valuable timber trees, fruit, nut and fodder trees, trees of importance for local wildlife etc and at last but not least any tall and old trees if since they are important habitats for numerous species because diversity is key to resilience
NFT For the tropics: https://www.echocommunity.org/resources/af337776-cdb8-4812-b3df-d11769f82838
But check for invasive traits before introducing any non native plants preferably use endogenous species. You can check there: https://www.cabi.org/isc/datasheet/34868
I again strongly recommend to talk to the chaikuni People the have experts for trees and know the endogenous plants.
For keyline identification if you do not have any high tech possibilities a simple A-frame:
https://www.echocommunity.org/resources/970ccc45-5508-4eaa-9ee0-f04bece59183

or a bunyip water hose level works also fine:

Thorny hedges as fences are a great idea. make sure to use shrubs wich provide more than just thorns maybe some Nitrogen, fruits or chicken feed as well
Best wishes J.

Another useful database for trees
http://apps.worldagroforestry.org/treedb/

#8

I’m bringing some NFT seeds back for Leucaena, Pigeon Pea, but Gliricidia seeds were out.

We have some Moringa at our house and want to spread it to our Permaculture site too, possibly prolifically. Most people there probably don’t know how healthy it is and I want to teach others how it can be their vitamin tree.

I’ll check the site for invasive plants and it might be fun to visit Chaikuni.

I’ve used water levels before (to build our house), and have an idea of what the keyline is, but I’m not sure how to use the waterlevel to find the keyline. I understand how to use it (in theory) to find the contour lines in order to make swales, but not how to find the keyline. I’ve heard the keyline might be ideal to place our off-grid jungle training house, so I’d like to know more about how to find the keyline.

The advantage with thorny hedges would help with security, though I’m not sure what species I’d use. Thanks for all those links!

#9

Yes, organic matter is the key to soil fertility in the tropics.

Have you considered a pump for moving water through pipes from your well to the plants? Maybe a treadle pump.
DIY plans at:
https://sites.google.com/site/treadlepump/buildyourowntreadlepump
At the very least put sealed containers in a wheelbarrow or cart.