Pruning Tithonia diversifolia for optimal biomass

[Tim_Motis]

How does pruning height and frequency affect biomass production of Tithonia diversifolia? This question was studied in Ghana by Partey (2010). He was interested in it from the standpoint of prunings for soil improvement. The idea is to transfer nutrient-rich biomass to the soil by leaving prunings on the ground or transferring them to growing spaces. As shown in previous research by ECHO, Tithonia diversifolia (also known as Mexican sunflower) is rich in nitrogen, phosphorus, and potassium, with levels comparable to moringa (Moringa oleifera) and lablab (Lablab purpureus) (EDN 134). ECHO’s North America Regional Impact Center staff in Florida also use it for making bioliquid fertilizer (EDN 157).

Partey (2010) worked with 5-year-old Tithonia plants spaced 1 m X 1 m apart. The plants were 2.3 m tall at the beginning of the experiment. He studied three cutting heights (25, 50, and 100 cm) and three pruning frequencies (2, 4, and 8 weeks between pruning events). Dry matter production (stems and leaves) was recorded each time the plants were pruned.

Here are some findings:
• Frequent pruning (e.g., 2 week intervals) resulted in high (≈ 90%) mortality of Tithonia plants. This was attributed, at least in part, to depletion of carbohydrate reserves with frequent foliage loss.
• Longer pruning intervals improved biomass production.
• Biomass production was highest with a cutting height of 50 cm.

Cutting plants to a height of 50 cm at 2-month intervals resulted in dry matter yield as high as 7.2 metric tonnes per hectare. It was recognized that results could vary depending on the age of the plants and location. If you are using Tithonia as a green manure, this data may be helpful to you.

Be aware that Tithonia diverifolia is considered invasive in many countries. Allelopathy may have a role in giving it a competitive advantage over native plants. Introducing it to new areas should be done with caution. Cutting Tithonia biomass as green manure could be a way of managing existing plants for obtaining green manure. It has been used as a green manure for crops such as rice and maize.

Here are a few photos of Tithonia growing at ECHO in Florida. The first one shows regrowth of green stem tissue after pruning:

Reference
Partey, S.T. 2011. Effect of pruning frequency and pruning height on the biomass production of Tithonia diversifolia (Hemsl). Agroforestry Systems 83(2):181-187. DOI 10.1007/s10457-010-9367-y.

[AFHGlen]

Tim, that is very useful. Thanks for sharing.

One question. Is there evidence that Tithonia has allelopathy properties?

[Tim_Motis]

Yes, that brings up a good point. Tithonia diversolia is considered invasive in a lot of places, and allelopathy has been posited in the literature as means by which it competes with native plants. I’ve added a word of caution to the original post about introducing it to new areas. Despite reports of allelopathy, there are also reports of increased yields with Tithonia green manure on crops like rice and maize. To my knowledge we haven’t observed negative effects of Tithonia used as bioliquid fertilizer. Others may have additional perspsective.

[AFHGlen]

My reason for asking is we are planning to begin planting it with our plantains as a chop and drop cover crop to provide nutrition for the plantains, but would be reluctant to do that if the allelopathic characteristics of it would hinder the growth of the plantains. What is your opinion of growing it adjacent/with plantains?

[Tim_Motis]

While I can’t speak from personal experience as far as trying this myself, I’ll share a few thoughts based on what I’ve seen here at ECHO in Florida and some findings from the literature.

First, we have T. diversifolia growing in close proximity to bananas in our syntropic ag planting/demo. The tithonia plants in the picture below were pruned, so they have been growing with the bananas for a while. While it’s not possible in this plot to compare banana growth with and without T. diversifolia it at least shows that bananas are growing quite well.

Looking at the scientific literature, I didn’t come across anything that addressed allelopathic activity of T. diversifolia against bananas, but found a couple that showed potential benefits of T. diversifolia. I’ll paste a summary statement with reference info below:

Liquid extracts of T. diversifolia improved resistance of banana seedlings to black Sigatoka disease

Tatsegouock, R.N., C.A. Ewané, A. Meshuneke, and T. Boudjeko. 2020. Plantain Bananas PIF Seedlings Treatment with Liquid Extracts of Tithonia diversifolia Induces Resistance to Black Sigatoka Disease. American Journal of Plant Sciences, 11:653-671. https://www.scirp.org/journal/paperinformation?paperid=100268

A six-month T. diversifolia fallow reduced two species of parasitic nematodes, enhancing the productivity of a subsequent planting of bananas

Gnonhouri, P.G., A. Zézé, A. Adiko, and K. Kobenan. 2019. Tithonia diversifolia crop rotation: an efficient cultural practice for burrowing (Radopholus similis) and root-lesion (Pratylenchus coffeae) nematodes in banana orchards in Côte D’ivoire. International Journal of Phytopathology 8(3):101-109. https://esciencepress.net/journals/index.php/phytopath/article/view/3029 (on this page, find a full-text version of the paper by navigating to “Issue” and then to Year 2019 under Vol 8 No. 3; clicking on that will take you to a page where the title of this paper appears along with a PDF download link).

Though not related directly to bananas/plantains, I found a review paper by Opala 2020 that gives some reasons why T. diversifolia as a green manure has not been as widely adopted by farmers as perhaps anticipated. It talks about the labor associated with cutting and transferring biomass. I can see where this could be minimized depending on your planting/row configuration. It also discusses variable nutrient composition and perspectives on whether or not it actually makes phosphorus more available to plants and increases soil organic matter (rapid decomposition is said to reduce its ability to build soil organic matter). In the section on “Response of crops to tithonia biomass,” however, it is encouraging to read that studies are mostly in agreement that crops respond favorably to T. diversifolia as green manure. It mentions a recommended rate of 5 t/ha of dry matter.

Hopefully, this info helps in your decision-making. Always informative to hear of first-hand experiences.

Tim

[Marie_Nsobih]

I love the subject. In my research farmers confirmed that tithonia improve soil fertility but however they prefer using it in compost production. Tithonia is very competitive amd inventive and farmers will remove them completely from the farm before and even after planting

[Tim_Motis]

Thank you Marie. It is encouraging to hear that farmers are using it in compost. It was interesting to note from the research by Partey (2010) that frequent pruning (2 week intervals) resulted in 90% mortality of tithonia plants. That could be useful info from the standpoint of making use of the prunings for soil improvement while keeping tithonia in check.

[Dan_Janzen]

I know for trees a pyramidal pruning system is likely to work best, like a Christmas tree is pruned. That is something to try. That allows all parts of the tree to get optimal light for photosynthesis and in the tropics this is very helpful since there is generally a lot of light, particularly in the dry season. It may be that the tree or plant will do better with a taller pyramidal shape in the dry season and a shorter pyramidal shape in the cloudy rainy season if it is grown as an annual. In addition, it may be better to have a steeper slope in the design on the west (or southwest or northwest depending on the latitude) where afternoon sun is more stressful and a shallower slope on the east side where morning sun is less stressful. The plants/trees should be spaced at an appropriate distance so that when a pyramidal form is done through sheering as we sheer Christmas trees no light gets to the soil but goes to the collective canopy. Also one variable that is almost never discussed is that you don’t need to prune the plant or bush at the same time. You can prune one side or not deep so that the plant or tree does not lose a beat at photosynthetic capacity. Too heavy of pruning at once is not good when you want biomass production because the plant or tree has to slough off part of its root system to regrow which is very inefficient unless you are trying to force transfer of nutrients to an intercrop. There are knives specially designed for this type of pruning if you are going to do large areas but a very sharp panga and thick plastic leg cover on right side leg and a steel toed boot are helpful to prevent cutting into your leg when swinging the panga/machete or long sheering knife. I looked at a lot of articles on this subject for my graduate research paper I wrote on alley cropping. This design also should help with maximal biomass production for Moringa or other trees as well and many perennial plants where the product desired is biomass. To get to a pyramidal shape quickly you may want to plant in a divot or a furrow if the soil has good drainage and use human urine if you are not using it for other higher value crops. And you can trim or nip edges as the plant starts to reach the height and diameter close to the surrounding plants/trees to get the desired pyramidal effect first starting with branches or stems that are in the spaces closest to the proximal plant or tree and later the ones heading in the “x” configuration to the corners which are furthest from their companion plants or trees. You need to leave the ones heading to corners without trimming longer without nipping so they can reach out further. A diamond or cross-checked planting pattern is best.

[Charei_Munene]

This is very interesting. Thanks @Tim_Motis for this crucial info. In Kenya farmers prefer it most for composting and making plant tea/foliar

[Christopher_Liow]

I am very confused by the chop-and-drop method; using Tithonia sp. as green manure in general.

Is Tithonia sp. not said to be aggressive?
Half of the world says chop-and-drop is evil because Tithonia regrows from every piece of stem takes/took over their land.
The other half of the world has no aggressive issue of it.

I have never grown it but I am planning to grow it which is the reason why I need to know.

I do have rich experience with Chaya, however. To cut the long story short, I LITERALLY love Chaya. It is the most aggressive species that I have yet to grow! I for one do not like to maintain anything as if my duty. The only thing I want to maintain is my sense of excitement. I want to be excited about plants. Sadly, I had to kill it to make way for other species due to space limit (and also to report what/which species works over here directly or indirectly assisting other people in my region or otherwise).

(I refuse to use the word ‘invasive’ due to valid reasons. Too many people wrongly use it when ‘aggressive’ is most appropriate. Big differences. Not game of pedantry nor semantics.)

[AFHGlen]

Christopher, we use it as part of our chop and drop and have not found it to root as easily as you are concerned about but maybe it would if it fell on bare ground during a time of daily rain. For us, we need to stick it into the ground for it to root.

[Stacy_Swartz]

@Tim_Emily_Tanner, @Roger_Gietzen , or @Will_Caswell may have perspective to share with you Chris!

Stacy

[Roger_Gietzen]

Hi Chris,

I may be able to help with your question. The aggressiveness of Mexican sunflower varies depending on the region it is grown. It’s tendency to root from stem cuttings is influenced by the age of the stem, it is more likely if it is woody and less likely when green. As Glen mentioned it generally only occurs if it is in contact with the soil.

I am familiar with using the plant in syntropic systems in Haiti, Brazil and I am also the one who planted the system in Florida at ECHO. We grow it intentionally to harvest the material for mulching and in this context I have not seen it cause any problems. It is normally cut every 2 to 3 months and placed on top of a pile of mulch where it dries and dies. In most of these regions it is, at best moderate in growth potential. In parts of Haiti it actually grows slowly and takes a few years to establish.

I have seen 1 farm in Brazil where the Mexican sunflower was not managed, and it grew very large. It ultimately spread through a large part of the farm by seed and became a handful for the farm staff. This was not caused by cuttings taking root. It doesn’t root from cuttings as easily as elephant grass, for example.

So I think there are some situations where it can be aggressive, but in the correct hands it can also be a great resource. I hope this is helpful.

[Christopher_Liow]

Hello Roger,

Ah ha! I now very much think that it is a weather issue!

I really do think that you and @AFHGlen are right.

I can say that Chaya is EXACTLY THE SAME as that said Mexican sunflower even when it is the most ‘hardy’ Euphorbiaceae from ECHO. We ought to start labelling it as Zombie plant! With this said, it does not root if I stack its stems out of soil. I guess there is a certain moisture level which it will put forth root/s.

Some such as Tillandsia and Orchidantha are far from zombie even when they put out roots almost no matter how dry the air is. It is because they are die rather easily compared to Chaya. My educated guess is the magic lies in latex/milk.

So yes, those Chaya cuttings (when I chopped and killed the plant) re-grow only because I placed them on soil as mulch. Plus they are in a heavy bunch with some other things which most likely increases moisture level high enough that those things resurrect.

However, there is an upper threshold of moisture level that Chaya cuttings fail to re-grow. I do not know how high of moisture level is ‘high’. They rot albeit with difficulty (since the latex/milk has super power). I intentionally killed them this way. It took me pretty long time to figure out how to permanently exterminate it. I could have applied triclopyr to save my time, I did not do it due to my lack of knowledge at that time; I was afraid that triclopyr in plant tissues will leak into soil killing nearby plants as triclopyr has a half-life of a few weeks (This, again, is temperate climate data. Degradation ought to be very, very quick in tropical climate. Similarly, I cannot see that organic matter took months to have its particles reduced as what people consistently say).

Zombie plants of any kinds may not be suited for my place if that is the case.

I intend to grow Mexican sunflower only because I need prolific blooms, prolific growth, not affected by external insults and offences. Space-effective, in other words. All because I have a very small space to grow stuff.

Ah… You mentioned that Mexican sunflower grows slowly. Frighteningly many “other people” repeatedly say that it grows quickly and therefore “invasive”. They do not only say it grows horribly quickly but also say it with strong emotion. So you see the confusion? I have never grown it before I tend to believe what I hear. Thankfully I do not like to blindly believe in anything.

You mentioned Haiti. I coincidentally bumped into College of Tropical Agriculture and Human Resilience, University of Hawaii at Manoa, website. Hawaii, and Haiti are a lot closer to the equator compared to Florida.

It appears that I do not necessarily need Mexican sunflower! There is only one issue, which is those tested plants are annuals. Sorghum, velvet bean, white clover, cowpea, sunn hemp. Velvet bean is very much a “short-perennial”, not bad, but in my humble experience, it climbs, grows horizontally, and becomes a stupendous mess. To make matters worse, it is not a prolific bloomer. Too much green stuff. Very bad in small space. Cowpea is upright at the beginning, it soon becomes semi-upright because its leaves are big, it has weak stem, also too much green compared to flower.

Worse still, the aforementioned plants are not good in self-seeding (I think that directly translate to “not aggressive enough”). The not-so-aggressive one may kill or inhibit seed germination should its leaf is massive, such as that cowpea. I need to watch after them tightly so that they do not mysteriously vanish. Insane worry and work for me to watch for seeds forming, protect seeds, collect seeds, kill weeds, sow seeds, protect seeds, make sure seeds germinate, kill weeds, make sure seedlings do not vanish. This becomes a duty.

I do not typically grow/germinate stuff in small pots and then transplant them, because I never want to make plants my duty. Nature is not like that, besides. I have plans to slowly make the pathetically small land to be mixed culture/multi-crop food land. Diversity is king to self-sustaining everything. Now is “building healthy soil”, and attract so-called “beneficial insects” phase. Something is super “wrong” with the soil at present.

There is no need for soil testing. I know FOR SURE it is human doing. I will not divulge the drama here. Hahahahahahah! About soil testing in Malaysia…yea good luck with that! I mean universities in Malaysia as universities generally offer affordable prices for their services to regular people such as yours truly. Sadly, their services are…never mind that. I have been asking ECHO for assistance on this matter.

I understand there is always trade-off. Nothing is perfect. This is the reason why I ALWAYS struggle to choose seeds.

Note : I fully realise that I am shooting myself in the foot. I could have grown plants with multipurpose. Food AND increase “soil health” simultaneously. Kill two birds in one stone. But what I am saying is I first start with plants which are extremely or the most efficient in ONE thing because nothing is perfect in everything. And considering the high temperature here that growth and degradation are expedited, not growing multipurpose plants should not be an issue as “everything being equal”; I will catch up on people who start with multipurpose plants.

[Roger_Gietzen]

I’m glad you found our responses helpful. Let me know if there are any open questions. Have fun in your garden.

[AFHGlen]

One more thing we’ve learned about planting this great plant is the cuttings can be planted either vertically or horizontally. If planted vertically (standing up), it produces one plant. If planted horizontally, it produces multiple plants. We mostly plant it standing up because it’s easier to punch one small hole in the ground and put the cutting in it than it is to dig a shallow ditch for planting horizontally. The second reason we like to plant it standing up is because we can see where it was planted and we can see if it roots and grows. Planted horizontally under the soil, it’s not as easy to monitor. Ours never have opportunity to flower because we are constantly cutting for either GMCC or fodder.

Planting standing up is better for us because we are “spot planting” in certain areas but if I wanted to plant a field, I would definitely plant horizontally in rows…like we do when planting tall grasses like king grass. Those ditches are very shallow…maybe 2 inches deep. In the past we planted in much deeper ditches but found it unnecessary work. Shallow works fine.