compost pH and N content

Hi,
I will be planting fruit trees next fall, mainly olives and almonds with interspersed Nitrogen fixing shrubs in a terrace whose soil is quite alkaline 8.1 below 30 cm deep and 7,9 in the first 30 cm
(which is a typical situation in here in Spain....very alkaline, high calcium, hi calcium carbonate soils). Rainfall is on the 600 mm/m2 range but some years it has gone down to 300....

This terrace was used up to two years ago for wheat crops and I know that the farmer who tended it used to fertilize it with pig manure (slurry I guess).
Accoding to the soil test, the technitian who did the test suggested that I only need to bring in some nitrogen because this is what is actually lacking, the other nutrients being apparently in good proportions.
I am not sure why only the nitrogen os lacking: if it is because the crops and subsequent natural ground cover depleted it, or if it was leached, or for whatever reason...

So I am wondering how can I bring this Nitrogen in again in an organic way. I was considering composted (or semi composted) sheep manure of a reseller nearby.
By looking at the lab data about this compost I see that it's ph is 8,36: eg higher than the soil's pH and I wonder if I should rather look for some other compost product with a lower pH
Its C/N ratio is 11,5 which is a bit bent towards being rather nitrogenuos, which is good..but also this should make the compost more acidic, isn't it? I am a bit confused on this last thing.
I also wonder what effect this type of compost may have on soil fungi (in case there are any at this point).

By reading Bryant Redhawk's posts on soil, I realize that at this point, eg after having already subsoiled the terrace which was quite compacted (clay-loam: 21% sand/43%silt/35,2%clay, in the bottom 60-70 cm
and silty-clay-loam in the first 30 cm), I should probably be better off fertilizing by injecting compost tea in the subsoiler grooves, alternatively I can just put a layer of compost around each tree once they are planted, I am not sure though how much compost (and which one) should I use if I do this.
Any help and other considerations appreciated

If you have access to composted sheep manure, Woo Hoo, that is great stuff to use for the purpose you mention, just fill the subsoiler groves to the top.
Being low on N is not really something to worry about so much, the soil test is designed for artificial fertilization of greatly tilled dirt, not really telling the soil builder what they need to know.

Most plants will do fine with a 10% level of Nitrogen in the soil, that is ammonium (the actual nitrogen provider that is broken down by bacteria for the plants to use).

Compost teas can be made from any compost you have, if you can use a fungal compost that is even better since then you are most likely adding all the biology the soil needs.

You can use sulfur if you really need to lower the pH, but if you get your soil organisms built up you probably won't really need to use sulfur or not a huge amount of it.

When you have other questions, just post them here in your thread, I'll be checking it.

Redhawk

Hi Bryant,
thanks for replying.

Right now (or rather last year, which is when the soil test was done) the N level (N-NO3) are/were 18 mg/Kg (i think it's the same as ppt/million) in the first 0-30 cm layer.
They say it is a medium value (in other terraces it is slightly, less like 13 mg/Kg).

Still I am not clear on the pH value of that sheep compost, does it matter that it is a bit alkaline being the soil already quite alkaline (8.1)?
Also the producer says that it isn't 100% composted, that is not a mature compost, would that still be useful?
Is sheep manure usually alkaline, by the way?

Regards

Ah, I was almost forgetting....how do I calculate how much compost shall I use?
If I plan filling the subsoiler grooves then it could be a considerable amount.

On the other hand, right now I have sawn a summer cover corp of sorghum-sudan grass + melilotus, so if this all grows as expected I guess I won't be able to see the subsoiler grooves after
cutting the grass in fall. The idea being producing root systems that will help loosening the soil and leaving afterwords woody biomass as mulch material which could start fungal networks to develop.
So I guess that in case I decide to apply that sheep manure I will have to do it on the trees themselves right after planting.

Antonio

on the alkalinity: aren't olives plants which prefer alkaline soil?

Hi Angelika,
yes they do but they also thrive in other soil types....I think there is a limit to the alkalinity they can bear while at the same time remaining productive.
The soil is already alkaline and I am not sure the it needs to be even more such.
Cheers

Aphids on fruit trees are usually an indicator of too much applied Nitrogen by the way.

Antonio, If the sheep manure is not fully composted, it would be best to complete the compost cycle prior to use on plants or trees, there are a few pathogens in most sheep manures that can transfer if the compost hasn't been at a high heat (160f) for at least 5 days.

Since you are growing cover crops (great idea), just finish the composting and use it around the trees, be sure to leave a fair amount of space between the manure and the tree trunk (that way you will feed the right roots and encourage root growth at the same time).
With a pH of 8.1, should you want to reduce that to closer to 7.0  you would want to use sulfur powder (can be added to the compost heap where you are finishing the sheep manure or just spread on the soil ).
I would use small amounts (dustings) so you don't over do it, you can add more easily but it is hard to subtract.

To calculate the amount of compost you need to know the volume of where you plan to use it (cu. cm or m or cu. ft.)  in this case you can calculate the volume of the subsoiler tine(s) and use that for the amount of compost should you go that route in the future.
With you already having planted, the roots will do most of that work for you this time so I would save the compost for the trees.

Plants don't need nearly as much nitrogen in the soil as most chemists believe, they are going on measurements of ammonia contained in plant  matter that they determine by Kjeldahl analysis.
Plants however get nitrogen from several sources when they are grown in good soil that has an active microbiome of adequate numbers, so unless your plants show that they are missing nitrogen, you really don't need to make any additions of it.

Redhawk

Thank you Bryant.

Still I have a couple of more doubts.

1) The cover crop will indeed use some of the N already in the soil, so actually the amount of N that will be available to the young trees when planted will be even less than the nominal quantity found by the soil lab.
2) In case I decide to go ahead with that sheep compost should I mix it with woody material while waiting to fully cure or should I just pile it and wait without any fuss?
Do you think that mixing mycorrhizal spores to this semi composted manure could be useful?

Lets take a look at how cover crops are generally used. We plant a cover crop to prevent soil from erosion, to keep the soil cool, to have live roots breaking the solid structure of the soil into more fractured, portions so water can infiltrate more easily and the soil will then also hold more water longer.
These are the main reasons for using cover crops. Once the cover crop has done its job, these plants are usually cut and the matter is left to decompose (rot) in place, that means all the nutrients those plants gathered for growth are now being returned to the soil.
When cover crops are used this way, there is no real nutrient loss and there can be a nutrient gain since one of the places plants gather nitrogen and other nutrients from is the air they breathe as well as through the roots, so it is possible to see a net gain in things like N.

I like to add as much woody material as manure to my compost heaps for manure, I use wood chips, straw, soiled hay, raked up grass clippings, forest floor litter that needed to be removed to establish pasture area.
With a 50/50 mix of manure to other organic, fibrous materials we can allow not only bacteria and fungi a foot hold in our compost but it also helps all the other beneficial organisms good soil needs to thrive and populate the compost.
The more micro organisms we can grow in our compost heaps, the better that soil will be once the compost is added to it, either subsoil level or surface level. (dug in or used as mulch)

Mycorrhizae are so important to good soil and good plant growth that I would never think of leaving them out of a planting, adding the spores to a compost in process is almost a no-brainer, why would you not give your new plants the one set of organisms that are well known to cause superior growth.
Almost all and any fungi found in soil provides a multitude of benefits to anything (microorganisms, plants, macroorganisms) growing in the soil. Fungi serve many functions (see my thread Nature's Internet and Bacteria-Fungi and Nematodes Oh My! for more on how the soil circle works).

Redhawk

A lot of directions on commercial nursery trees say not to fertilize, or to hold off for first three years.  It’s not like annuals with their flash or ephemeral life.
I enjoy Stefan Sobkowiak youtube shorts and in the last one he talks about aphids being a sign of out of balance fetilization and ussually too high of N.
In it he had an example of a guy who had a habit of peeing near a tree, and that one convenient tree having more aphids than the others that they thought were grown in the same conditions. There is more than one way to gently naturally raise that N.  One of the meals would move your ph towards neutral and add N; I don’t remember which one.

I was looking for a foot of new growth on 3 year old on site +2 year at purchase walnuts and didnt get it.  So I tried composted chicken manure and still didn’t get it.  So I tried a blood offering and still didn’t get it.  I have acidic soil in a mixed forest and my compost is mostly fungal chicken droppings in woodchips.  I dont know what my limitation is but most trees don’t need much Nitrogen and I now believe through observation that wasn’t my limitation this year.

Thanks to both Bryant and Jim!

By the way, I wonder how I can interpret the measurement of the micro/trace elements that the lab found. Is there any standard interpretation of lab results that can be used to understand
the lab findings, or else what can one extrapolate from them?
For example this is what was found in the first 30 cm in one of the terraces and the labs evaluation, but I am not sure how to use this info:

Mg ->  155      mg/Kg .......... medium
Ca ->4173      mg/Kg ......... very high
Na ->    48      mg/kg .............non saline soil (ok this is easy...the soil isn't salted which is good news!)
S  ->     73      mg/Kg ...............medium
B  ->       0,41 mg/kg ............medium
Fe ->      3,07 mg/kg ............medium
Mn ->  < 1,00 mg/Kg .......low <br /> Zn ->  < 1,00 mg/Kg .......low <br /> Cu ->  < 1,00 mg/Kg .......low <br /> Mo ->  < 0,10 mg/ Kg .....low

Ok, this is the industrial view of these nutrients so most probably there is not much to worry about, and I guess the cover crops that will follow can reverse these (apparent) imbalances

The items listed as medium are ok as is because as the microbiome increases in numbers more minerals will become available to the plants.
Soil tests give you the Water Soluble minerals, not the actual total mineral content (most minerals are still bound up in the rocks, which bacteria break down).

The Mn, Zn, Cu, Mo, being low could be a concern, watch the leaves of your plants, if they start showing yellow veins or green veins and yellowing leaf material then you need to increase those (you can use out of date human vitamins with minerals 4 tabs to a gallon of water).

The big thing to do is always add good aerated compost either into or on top of the soil and use compost tea to water plants at least once a month, twice a month is even better.
Once you get a thriving, well populated microbiome in your soil, your plant nutritional needs will be met easily.

Redhawk