Trees with deep taproot

If one has soil that doesn’t drain exceedingly well after heavy rains and one wants to plant trees in an attempt to “punch holes” into the soil to improve the drainage, is Leucaena about as good as it gets or are there others with a stronger taproot? Central America 700 feet above sea level.

On the upper level, the soil is somewhat sandy. We have dug down 3 feet and have not hit any hard pan or rock.


Sounds familiar - however the soul at my problem site is heavy clay and in a floodway. You said your soil is sandy - what then is impeding drainage?

Are you wanting to grow a crop on this land?

We planted fruit trees during the past six months of dry weather but now that it has begun raining I have begun to observe this water logging in areas that surprise me given the level of rain after six dry months. This land is a new purchase and so I am not greatly familiar with it’s history.

This piece of land receives a lot more water than from the rain because it is at the base of a mountain and much of the runoff from the mountain, flows through that area. Nevertheless I would’ve thought the water would drain more quickly given the sandy soil. I don’t really know how to classify the soil but it does have sand in it although it’s not approaching being pure sand.

I am assuming there is some short of soil underneath the sand that does not pass water very quickly. For that reason I’m wanting to plant legume trees with very strong tap roots in an attempt to “punch through” the layer that is slowing the flow of water. The plan all along has been to include legumeous trees but now the plan will include a larger number and I’m trying to determine which might be the best.

As far as I know Leucaena doesn’t really like waterlogging too much. Try gliricidia as well. And vetiver grass will grow down to about 4m as well.

We have a similar situation here in Central Tanzania, but we have several indigenous trees that fit the bill well. I don’t know about South American trees, but you might find a suitable species here:

Here it says that leucaena is well fitted for the job you have:

Thanks Martin for the ideas and information. We are also growing vetiver for that purpose in that area.

yes good advice from Martin. Would suggest 1. understanding your context - history and soil geology - it sounds like you maybe don’t have the full picture (a lot of assumptions), 2. think diversity - not just Lucaena but a range of species that have that function, focussing on local. Good luck!

Those are two good points. Initially for the sake of brevity I did not include a list of the various trees we are growing in that area. But it does include a wide variety. However, now in laying out some vetiver contour lines, I was wanting to add a legumes tree with a strong taproot.

Maybe I should make a separate posting seeking a volunteer to come and help us understand the soil. I had a recent college grad with classes in soil classification who was going to come for five days but then he got a job…

Well Guava is not deep-rooted but it will tolerate both drought and excessive water so it could make a good intercrop with another species so you would have income. The Lucaena and Gliricidia are both great for improving soil and has a deep tap root. You can even hedge lay the trees on the ground as an understory to fruit trees and regularly prune or rip branches to use it for mulch/green manure. You grow it tall, gradually/progressively eliminating a few of the most competitive branches with the largest diameter relative to the stem diameter and then lay it over cutting just enough to make it lay flat on the ground. A younger tree can be pegged to the ground without breaking it if you twist it as you lay it over. You could also make a diversion ditch to move the water coming down the mountains away and direct it where you want it which could be useful for other crops as irrigation or to fill the aquafer or a pond, etc. To me income generation is important to maximize the blessing to others and to further the Great Commission so if you have more than one option pick the one that maximizes income.

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I appreciate those ideas Dan. While I am a great believer in growing diverse plants together it had not occurred to me to grow together a diverse selection of smothering crops and the various selections could be of different heights… like the difference in Canavalia and Pigeon pea. Because of their deep roots, intending to plant pigeon peas with vetiver but never thought about with the Jack beans.

I also appreciate your frequent mentioning in different posts of being income conscious in the planting plan.

However your idea of lying on the ground Leucaena and Gliricidia is a new concept and I didn’t fully understand your notes on it. Could you elaborate? Thanks!

The answer to your question Peter remains elusive of what is impeding the drainage. With a post hole digger we dug a 4 foot deep hole and the deeper we went the more sandy the soil became…not a lot more sandy but certainly not less. So, not sure what is impeding the drainage but whatever it is, it is down deeper than 4 feet. But that discovery gives me hope that perhaps plants and trees with deep tap roots could be helpful in facilitating drainage.

One of my strategies will be to plant more Leucaena and Gliricidia seeds directly in the field because it seems to me that planting seeds directly in the field will result in a stronger taproot as compared to rooting cuttings or planting in a nursery first and then transplanting in the field. I feel this is especially true of rooted cuttings but not as sure about seeds planted in the nursery first. If any of you have experience or knowledge on that topic, I am all ears…and eyes.

Hey Glen, sounds like an unusual situation…

Sounds like your in the tropics (like me - most fo the time). Bananas might love the wet site. We have some amazing bananas where we are in Timor-Leste - a dozen varieties. My favourites are the female bananas- red with amazing aroma and depth of flavour.

I think if you scatter leaceana / gluricidia seeds in a row or two nd cover them with soil you will quickly get germination. One thing I want to try (later this year) is to do 1 metre wide rows of them - with say 3 rows of seeds. Then when they get to 1.5 metre tall then cuts them back to 50 cm using the loppings as mulch (or forage). Might serve two purposes - improving the soil as well as maybe penetrating the impervious layer… It s a sloping agriculture land technology (SALT) out of Phillipines.

[salt agriculture terraces - Google Search](salt agriculture terraces - Google Search agriculture land,› teca › technologies)

Just thinking - could also be a big slab of rock underneath!

I like your idea Peter of planting the Leucaena in a narrow but intense band.

The well driller in the area says he never hits a slab of rock in the area but anything is possible. When he drilled our well, which is about 250 meters from the area with the slow drainage, he hit no rock slab.

Has anyone else noticed that when rooting cuttings as opposed to planting seeds, that seldom do taproots develop but instead and abundance of lateral roots develop? I have mostly observed this with Gliricidia but will begin noticing with other cuttings. However whenever planting seeds of Gliricidia or Leucaena, a strong taproot quickly develops.

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Jacaranda tends to have less surface roots, and to be a stable tree. Colorful, hardy, tolerates various soil conditions (even anaerobic), good timber, etc. Originates in South America.
I have had trouble with Leuceana toppling due to windthrow and surface roots. They are also VERY invasive (here in Boma Ngombe) in some soil conditions (volcanic sandy loam) - but FAST growing and decent fodder.

Thanks Jeremy for the suggestion. Is it a good fodder tree for feeding animals? Does it fix nitrogen?

Hedgelaying - Wikipedia is the Wikipedia site but there is not much for diagrams there.
Agroforestry Techniques for Maximizing Income | is my presentation at the Arusha conference. There you will see various forms of hedgelaying that focus on high value cropping and are derived from but yet very different from the ancient techniques in terms of how they are applied. Some of these techniques can be utilized temporarily (some used permanently such as field boundary) until more efficient modern methods began to be used due to high-income generation. I want people to have more versatility over time so people start to do a comparative analysis on income per hour (or return on investment for when you have savings) with record keeping with more potentially more efficient methods made possible from savings so they can fulfill the Great Commission which is the maximal pathway of human flourishing for the earth. As much as we are proud and love a really cool practice it must yield itself (subject itself) to income per hour qualification at every stage of savings and reinvestment. That is the excellence standard that God is calling us to. We should really consider whether we are practicing something as a hobby or as the pathway to the highest income source to free up time and money for the Great Commission. We should be reducing our hobby farming and increasing our involvement in the Great Commission. ECHO is a great place to get advisors and then you take the best advice and you run comparisons between at least two. With irrigation, mechanization, more efficient use of labor (i.e. piece-rate) and access to all the tools God has given us, not just the ones approved by the organic-only group, we can achieve this together.

Dan, I just found your document here on this website describing how to do living fences. Very well done. Glad to find it. Looking forward to digging into it and digesting it more completely. Thank you for that contribution.

I’m surprised no one has asked this yet, but I think there might be some bigger geological/topographic issues at play. How big is the mountain you are talking about? The real question behind this is how big of a watershed/landmass do you have draining onto your property? This is a fundamental question that needs to be answered or approximated before spending loads of time on planting things if you are looking to “solve this problem” because you could everything right and still have flooding. Your land size might just be too small and have too much water coming in during certain times of the year. The only thing to do in that situation would be to see what people “up river” or at higher elevations are doing with their land and encourage them to do what they can to hold more water and minimize runoff.

Also, do you notice differences in drainage speed/capacity at different times of the year. If you have a long dry season, with heavy rains at the beginning of the year, you likely will have a tough situation with all but pure sand. Soils need time to absorb water after being cooked for months without access to any rain and limited humidity. Think a completely dry sponge vs a slightly wet one that will be able to absorb more water.

Thank you Tyler for your thought provoking notes. One reason I don’t know very much about the land is we only recently purchased it. One of the motives in buying it is to try to slow down the runoff because the runoff has caused major erosion problems on our adjoining land which is downhill from the land we are discussing.

I don’t believe there’s much I can expect to be done upstream from us because the locals here generally lack concern over erosion. I see major sections of farms eroding away without the farmer seemingly noticing it even when the farmers have more than enough money to address the issue which is the case of the landowner uphill from us. But, I plan to try.

There is a public dirt road between our property and our uphill neighbor. One of the things I have done is wherever the water comes into that road, which is multiple places, it was all being funneled into one area of our property. I have change that with diversion ditches in the road that sends the water in multiple different directions all on my property but different parts of my property. A small portion of it has been diverted to a different neighbors property. The neighbor gave me permission to do that.

The other thing we have done is develop contour lines spaced out going down our field and planting those contour lines with double rows of vetiver. We have also begun planting trees with strong tap roots in hopes they will penetrate deep into the soil creating channels for water to drain downward.

Back home in the states, I am familiar with 2 1/2 inch hand augers that can dig down 12 feet to examine the soil but I haven’t found that available here. Perhaps I will need to ship one.

Your point is well taken that there may just be too much water coming off the mountain to be able to be absorbed during extreme weather… like hurricanes. I will be content if we can control it when there is a heavy thunderstorm delivering 3 inches of rain.

Bottom line is we are trying a multi faceted approach including diversion ditching, planting vetiver grass on contour lines, planting lots of trees with penetrating taproots and planting a lot of deep rooted grass… (Pennisetum purpuphoides)…we favor a variety called Taiwan because it is highly palatable and nutritious and has a very succulent stalk that our sheep will eat without needing to be chopped.