Ultisol scorching plants

[gatewood]

Hello ppl! new member here

I've been trying to grow crops on a subtropical rainforest with an ultisol kind of soil (red and lots of iron in it) in Mexico. It presented the following problems (that I fixed with the following solutions):

1. Low pH (originally at about 4.5): made some bonfires to get lots of wood ash to raise the pH (in now stands at around 6.7).
2. Low fertility: composted a lot of plant matter and started growing legumes to fix nitrogen.
3. Clayish and waterlogs easily: since I'm close to the sea, I collected sand to get a more loamy soil (I washed the sand to get rid of the salt).
4. Rains erode and wash away nutrients: started making charocal to use as biochar and retain nutrients.

My compost pile has grown very healthy (it doesnt stink at all) and quickly devours almost any material I throw in and plants seem to enjoy a high supply of nutrients from it (no effects of nutrient deficiency), however, there's one more problem that is still causing crop failure:

Leaf scorch - Wikipedia

en.wikipedia.org

There's something causing a lot of root and foliage scorch (especially the roots, which get eaten away completely) on all the plants around here (miles around). The damage is very similar to that of herbicide burning like flumioxazin (as can be seen in the pictures), but I live miles from the closest town and there's no way this could be caused by herbicide. I'm almost certain that this is no infection either, as I've spotted no root rot and plants that are uprooted and placed in water actually begin to recover and grow healthy roots.

I've been looking around for answers, but this seems like a very specific problem. Any idea of what is causing this?

 

[PSQ]

Have you had a soil analysis done to see if there was any obvious excess of any particular element/s. It sounds like a toxicity issue, but then again I know diddly squat about tropical soils.

 

[Bogweevil]

Hello ppl! new ...
I've been looking around for answers, but this seems like a very specific problem. Any idea of what is causing this?

Distorted foliage consistent with aphid or other sap sucking insect attack -- have you checked beneath the leaves? You might need a hand lens.

Holes on stems consistent with fly larvae attack - consider dissecting stems to see if you can find larvae or pupae.

 

[2wheels]

maybe your burn ash is soaking up the nutrients.

 

[gatewood]

Distorted foliage consistent with aphid or other sap sucking insect attack -- have you checked beneath the leaves? You might need a hand lens.

Holes on stems consistent with fly larvae attack - consider dissecting stems to see if you can find larvae or pupae.

Thanks for the input , I'll definitely gonna research those pests. However, I've been growing some other crops (for about 2 months now) using soil from somewhere else and they're growing splendidly well, showing no symptoms of anything (forgot to mention that, sorry). Furthermore, as I said, uprooted plants that are placed in water immediately begin to recover.

Have you had a soil analysis done to see if there was any obvious excess of any particular element/s. It sounds like a toxicity issue, but then again I know diddly squat about tropical soils.

Hmmm I dont think there's any excess of any nutrient, rainforest soils are one of the most infertile ones there is.

Is there's a poisonous element/compound that can produce these results, or something similar?

 

[PSQ]

Hmmm I dont think there's any excess of any nutrient, rainforest soils are one of the most infertile ones there is.

Is there's a poisonous element/compound that can produce these results, or something similar?

You need to look at the evidence, and that starts with a broad spectrum soil analysis.
Googling ultisols suggests a shortage of calcium, magnesium and potassium. Adding enough wood ash to raise the pH from 4.5 to 6.7 may well have knocked something else out of balance, and for the equivalent of £25 per sample it’s money well spent, even just to prove that the chemical side of your soil is in good condition. Without it everything else is just guess work.

 

[gatewood]

You need to look at the evidence, and that starts with a broad spectrum soil analysis.
Googling ultisols suggests a shortage of calcium, magnesium and potassium. Adding enough wood ash to raise the pH from 4.5 to 6.7 may well have knocked something else out of balance, and for the equivalent of £25 per sample it’s money well spent, even just to prove that the chemical side of your soil is in good condition. Without it everything else is just guess work.

This kind of damage occurs whether I add my compost or not. I guess there's nothing else I can do. Thanks for sharing your thoughts guys

 

[Yale]

@deleted user 837354

 

[deleted user 837354]

Appears as a kind of pest or disease attack: looks like some kind of rot on the stems to me?

If you are close to the sea could it be an issue related to sodium/salt?

If you have a big excess of iron you could get all kinds of nutrient lock ups. Iron is one of the worst for it. We will be guessing unless someone knows that particular crop plant(s) well and you have a detailed soil analysis.

 

[gatewood]

Appears as a kind of pest or disease attack: looks like some kind of rot on the stems to me?

As I said before, all plants that have been uprooted and placed in water (about 30), immediately began to reverse the damage.

If you are close to the sea could it be an issue related to sodium/salt?

Hmm I'm not that close, I'm about 150m inland and 30m above sea level (I'm surrounded by a subtropical rainforest). Besides, the compost I've been using has been washed numerous times and should have lost any salt content at this point.

If you have a big excess of iron you could get all kinds of nutrient lock ups. Iron is one of the worst for it.

That is a lot more likely, the soil is red as f***, I think I even got a bunch of red, hematite rocks ready to be sent to the blast furnace.

We will be guessing unless someone knows that particular crop plant(s) well and you have a detailed soil analysis.

Basically ALL plants suffer from this, the native flora seems to have developed resistance, but symptoms are still prevalent, albeit less severe (the shots of the distorted leaves are from local plant). Small plants and seedlings seem the most susceptible: climbing plants and my crops, beans, tomatoes, garlics, avocados and peppers.

The only one that seems to resist it no problem, are palm trees.

 

[renewablejohn]

Have you tried growing the crops under shade netting.