Salinity help

We live north of Houston, TX and have acidic clay soil. Our avocado trees have leaf tip burn from excess salinity. We are just beginning to start the food forest - hazelnut, garlic chives, avocado, berries, pears, figs, and comfrey so far. Are thereany plants that can help soak up excess salts? Or any other help? We plan to add natives like pawpaw next year as we can afford to, but we wpuld really like these avocados to do well!

Hi Katie. This can be a little complicated. Have you had a soil test done? If not, the information from a soil analysis is almost necessary to remediate your soil. It's necessary to identify which salts in the soil are in excess, then you will be armed with the data to choose the right methods for alleviating the problem. For example, in some cases if there is excess sodium in the soil, adding calcium or lime (or calcitic lime for that matter) may help. It could also be too much nitrogen. The leaf tips in your picture could also be symptomatic of excessive water, which can deprive the roots of oxygen. Both excessive water and excessive salts can result in root mortality, which leaf tip burn can be a symptom of. If your soil is well draining, however, one method to alleviate excessive salts is to literally flush the salts out with water. There could also be another culprit, bacterial leaf scorch. There really are too many variables here to identify a remediation technique that will be successful without a soil analysis first.

Thank you for responding! I have added a pic of our soil analysis. It is clay soil, so not very well draining, but we haven't had a high amount of rain - in fact we have had almost perfect rainfall this spring. We did put the trees a couple inches above ground level and burm them and mulch them. We are working on getting organic matter into the soil since there is no topsoil left and no nutrients in the soil, but it takes time...we have added manure, straw, wood chips, and compost on top.

Ok. Interesting. Well, your pH is dismal. It's great for blueberries tho! I've attached a pH/nutrient availability chart so you can see as things get acidic, nutrients aren't available for plant use, even tho they're there. So your plants look sickly in the picture, not just looking at the leaf tip burn, and the pH is why. I would apply some calcitic lime to start raising your ph, with an eventual target of 6.2ish - 6.5 on the high side. This takes time. So tilling soil is a hot topic for debate, but even some of those who are against all tilling, will say tilling once at the beginning to aide in incorporating organic matter can be a good step, since that soil almost can't be made worse. Think of it as setting the foundation, then you never till again and apply your amendments right on top, constructing a healthy soil food web.

Edit: I would add calcitic lime at a rate of 12lbs/100sqft. This is the rate at which was recommended for me on my soil analysis that had a pH of 5.2. In hindsight, personally I would have applied 6lbs/100sqft and then another 6lbs/100sqft like 3 months later. Things like a heavy downpour can take the dissolved lime away as runoff if the ground can't absorb the water at an equal to or greater rate than it falls from the sky.

Great! Thank you! We have tilled lime into our garden beds for the same reason - one tilling at the beginning just because the soil is so bad - and tilled in compost, azomite, green sand, lava sand, lime, and mychorrizal fungi. I'll have to look up calcitic lime since I'm not sure what ours is that we are using (it was given to us by another gardener). Can you top dress lime under mulch? Ee can till it in around the trees, but obviously that won't work right around the root balls...

And yes, we have tons of berries and azaleas that are flourishing...but we also know lots of people who grow avocados around here so we know it's possible. We have some uncleared forest in the back of the property that has much better ground, but this ground has been kept cleared and mowed and raked for many years until we bought it last year.

Thank you for your help, that chart will be great!

Oh, and why would we need calcitic lime with there being calcium in the soil already? Wouldn't adding plain lime make the soil calcium available? Thanks for your patience, weare just starting out and don't know much yet.

In order for any amendments to really work you need to check your soil biology. Odds are that a good compost tea will help tremendously.
Speaking as a soil scientist;
One of the main problems with soil tests is that most soil scientist forget or ignore that it is the soil biology that makes any nutrients available to plant roots.
We are taught that the only thing to worry about is what compounds are present in the soil.
Unfortunately, without the microbiome to make these compounds available for uptake by the roots, those compounds just sit in the ground, doing nothing.
Soil is a living organism, made up of many individual critters; bacteria, fungi, protozoa, nematodes, etc.. These critters are what eat the compounds, break them down and make nutrients available for plant uptake.

Trees are dependent upon mycorrhizal fungi, these fungi invade and live inside the roots where they help make nutrients available for uptake by the tree.
With out them, you will see some improvement but not as great as is possible with the right fungi and bacterium surrounding those roots.

To break up the clay, daikon radish, alfalfa (Lucerne), clovers are good items to plant prior to planting a tree in that clay soil.
These will help to break up the fine particles with root structures that will turn into humus when you chop and drop.
The daikon is great at this, the edible root grows huge, driving deep and then when you chop the top it begins to rot and turn to a column of humus.
These plants also bring good bacteria and fungi to them through the use of exudates that chemically call them to congregate and provide nutrition for the plant.
All this improves soil structure and biology so that any amendments you add do what you want them to do.

Redhawk

Yes you can put lime under mulch. I like what you've tilled into the soil. Note that the mychorrizal fungi are completely dependent on living roots to thrive and do their job. There are other microbes you can add to further improve your soil if you desire.

So I recommend calcitic lime because of your calcium:magnesium ratio. First let it be clear I am not a soil scientist. I have a basic understanding of soils and soil health of which I've obtained thru books and still have much to learn. So, ratios. There are a couple nutrient ratios which must be in proper order for the rest of soil nutrition, microbial life, root health and plant health to succeed. They seem to be calcium:magnesium of 10:1, phosphate:potash of 2:1 and a potash:sulfate of 1:1. For an example in this discussion, we'll look at the cal:mag. Looking at the values on your soil analysis, the calcium in the soil is 254ppm and magnesium is 41 ppm, or a ratio of about 6:1. it's heading in the right direction. In the decades prior, agriculture was focused on NPK and the quantities in soils, largely ignoring the importance of calcium because if was largely not understood. Farmers were aided in their endeavors by fertilizer salesmen who spoke of mainly of NPK, and you apply fertilizers to make crops grow successfully. Agricultural science now understands how imperative calcium is, as it is necessary for all of a plants biological functions, including nutrient uptake thru the rhizosphere, and on the soil side of science calcium is absolutely necessary for the microbial life in the soil, which make the other elements available for plant roots to uptake.

The above barely scratches the surface of soil management and it sounds like you are pretty serious about gardening and are putting thought and consideration into your gardening adventure. I highly recommend reading some books on soil health and management, like Building Soils For Better Crops by Fred Magdoff & Harold van Es, Building Soils Naturally by Phil Nauta, The Soul of Soil by Joseph Smillie, Building Soil by Elizabeth Murphy, and others. You get the idea Those books and others will guide you to successful gardening through healthy soil practices. Regardless of what you're trying to grow, they all grow in soil. Healthy soils yield healthy plants, which rarely get infected with disease and infested with undesirable insects.

I noticed your soil analysis came from the county extension. They gave you good information regarding the quantities that are present in the soil, but there are better soil tests out there, and they do cost more. Better soil tests will give you base saturation values (sometimes called a base saturation test) and also a Reams test (named after Dr. Carey Reams who really was a soil scientist). I'm not proficient in my understanding of those tests to explain them to you here, but they are explained in some of the aforementioned books. The Googles will also explain it

I hope this was helpful and I'll try to answer more questions if I can


Edit: The other microbes I mentioned in the first paragraph, those include Effective Microorganisms, or EM for short. I purchased my EM from a company called Teraganix. There are other producers of EM too. There are also soil inoculant blends containing bacteria like Bacillus, Streptomyces and Pseudomonas, among others. All are good guys we want in healthy soils.

Redhawk- I had no idea you were a soil scientist! I think that's great and you ought to write a book on soil. I would love to read it.

Katie- Listen to everything Redhawk says

Wow, thanks both of you for all the great info! You're right, we do need to read some books on soil management...that'll go onto the list of to-read next time we get more books!

We'll go ahead and add calcitic lime and maybe try digging in some mycorrhizal fungi around the tree roots. I think we'll plant some daikon between the trees, also, and maybe some clover. We just had the septic replaced and the soil is totally lifeless orange clay 8 ft down! Thank you, redhawk, for all the soil bio advice - we definitely know that the biology is really important! We also have chickens running through everything and are trying to get some life into the soil so that the microbiome will come back.

Will report back once we have done these things! Thanks again!

hau James, Instead of a book, I am working up a thread to post in our soil section. I want to put it all together so that not only the mineralization, friability, pH and other parts we look at when testing soil but also the microbiome and the needed concentrations required of those organisms for truly awesome soil.

I just got through with a series by Elaine, study of soil and all that creates it are for me an ongoing learning experience. I'll be bringing much of the wisdom she imparted to me into the thread I am working on.
I am hoping I can put up the first post in a week but it might be two weeks, so much is going on right now, time for writing is scarce.  The Eat your Dirt campaign was awesome.


Redhawk

Redhawk- Fantastic! I'll be looking forward to reading that.

Katie- Real quick on your mychorrizal inoculant, check the label and see if it contains both endo and ecto mychorrizal spores and colony forming units. Generally speaking, endomychorrizae populate the roots of common food crops that we grow in our gardens, and grasses and other plants, but not a lot of trees. For the most part, it's the ectomychorrizae that live on roots of trees and will not colonize food crops and grasses. There are exceptions to both, like the blueberry bush. From what I've read it's my understanding neither will colonize blueberry roots. Again, I'm not an expert, but having an inoculant containing both endo & ecto kinda covers everything for simplicity of inoculation.

When it comes to mychorrizal fungi it can get confusing but it is actually pretty easy to understand when you know how these little guys work.
Ecto means outside of, these fungi do their work by coating or laying near roots, they eat several different bacteria, thus releasing the minerals those bacteria have eaten. They work for our vegetable crops, grasses and bulbs.

Endo means inside, these fungi actually invade the cells of tree roots (rather exclusively) and they eat bacteria, pull minerals released by the Ecto fungi and give them to the root cells. Most trees can't directly pull these items into their cells so the Endomychorrizae do it for them.
With out Endo fungi, trees can grow but that growth will be much slower and health might not be superior as it would be with the Endo fungi in place.

Now the really cool part of this is that the two will work together as well as work separately.
It is always best to use an inoculation that contains both, so you get as complete a coverage as possible.
Most of the suppliers of mychorrizae have both types in their products.

Blue berries like soil that is so acidic that neither of these types of fungi like living in the soil surrounding the bushes, they work more directly with bacteria and two species of nematode and four species of protozoa. Which, are easy to grow just by making really good compost.
If your compost is sweet smelling, crumbly in hand, darkish brown but not black, then you have these super organisms in good quantity. A top dressing with that compost will get them where you want them.

Hope that helps some folks

Redhawk

Thank you for the clarification, we'll check thefungi and apply appropriately!

Dang I think I had that backwards. Redhawk, Thanks for clarifying. You saved the day

No worries James, it is easy to get confused when it comes to soil and what is usually recommended for amendments and quantities of those amendments.

Since I brought that last part up. When we do a soil test, no matter how complete it is, we are going to recommend what can be termed as over kill as far as how much of what to add.
This is a constant within the community (soil scientist community) because, we are working from a knowledge base founded in "commercial agriculture needs".

Here are some actual needs for soil along with "normal" recommendations you would see in your soil test results.

Normal recommendation                                    Actual Needs

Nitrogen 150-1000 ppm                                        0.1-0.5
Phosphorus 50-100ppm                                         0.1
Potassium 100-400ppm                                         0.2
and this overkill quantity recommendation  continues all across the board. The highest any mineral would need to be is 0.5 and that is for Magnesium and Iron, Sulphur comes in second at 0.4 and the  low guy is Zinc at 0.04

Those actual needs figures are what we find in naturally productive, untouched soil samples. Since "farmers" till the heck out of their soil turning it into dirt, they have to add far more in the way of amendments just so the tiny amount actually needed is available for plant roots to take in.
Those fields that have been no till for more than five years have no need for amendments (doesn't mean those farmers don't use fertilizer like they are told they should, just that they really don't need to).

Redhawk

That makes great sense. Our uncleared forwst has beautiful soil that grows very well. I really want to get that tested to compare, and I may also plant some veggies and such back there just to see ho they do.

If you're planting in your forest this spring, I'd suggest trying kale. I grow it under a tree in my yard and it survives the summer that way. I don't get much production out of it during that time of year.  It's off to the races after the tree drops it's leaves. Frosts kill the pests and the plant is already well established and ready to grow good sized leaves for the kitchen all winter.

Great! I was actually planning to start kale in there, but I think it will have to wait until fall. We are extremely hot here in the summer and are already hitting the 80s and even 90s now. But I am reallyexcited to grow some differentpere nial kales and maybe some hot weather greens as soon as I can get some. We are putting in fruits, veggies, gardens, livestock, and infrastructure all at once, so we only have so much money to go towardnew plabts at the moment.

That summer heat is specifically why I was letting you know about planting the kale under trees. If you look, I'm in Central Texas just a little north and a few hours west of you.

But I definitely agree with focusing on getting a good infrastructure in first. Kale is very easy to grow from seed, so when you are ready it's inexpensive to get a good amount growing.

I didn't realize you were so close - maybe I'll try some kale seeds that we can pick up for a couple of bucks. We actually have a shady planter that runs along our garage that I'm thinking about planting with greens if we can keep the chickens and ducks out of it. Thanks!