Fertilizing oak trees.

[Angus 1895]

Here’s the deal.

Get you some miracle grow. ( I like mir acid)

Go outside…….apply some where you can monitor it.

The stuff makes plants grow……..

 

[FarmerDan]

I will go out on a limb here. Soil fertility is not the limiting factor in production of acorns.

An oak tree is not a corn crop. You can apply all the fertilizer you want to a corn crop, but if the other factors required for yield, singly or in combination, are not present there will be no increase in production when the other key factors are considered.

So, I would suggest fertilizing oak trees might help acorn production if all the stars align, a situation with a very low probability. If you want to fertilize, spend your money and hope for the best. Except for the lightening of your wallet, nothing bad will happen to the oak tree. There are standard protocols for fertilizing large trees. Employing one or many will probably increase the odds of effect when everything else happens as we would hope.

And hope springs eternal. It's your choice but I think your time and effort and money is spent better elsewhere.

 

[Tree Spud]

I think this is one of those things where common sense should prevail.

The oak tree root system will mirror the above ground canopy. The tree's size and productivity is ultimately guided by the soil nutrients and consistency of water moisture available. There is also the added variability of whether the individual tree is genetically a reliable annual producer of nuts.

Even if you did fertilize, and for a single mature oak that would probably require 150-200 lbs given the root system size, what % of mast production increase do you really think you will get?

 

[omicron1792]

That's pretty much exactly my take on the whole thing except for the significance of the drought years. I suspect that drought can negate the effects of fertilizer, and I would be willing to bet money that in a series of two or three consecutive years, starting with the application of the fertilizer, there would be an increase in production and wildlife use of the fertilized trees if there was normal rainfall or supplemental watering of the trees.

That is to say, I do tend to take the researchers in this study at their word regarding their findings, but I think their results are incomplete, and I suspect the drought conditions were a significant factor in this particular study.

Agree fully. And I fertilize my young trees! I have always just thought for mature trees putting fertilizer on ground around it would make minimal impact. Agree with @FarmerDan that getting some concentrated fertilizer to deep roots might work. One of y’all figure that out for me!

 

[Catscratch]

Agree fully. And I fertilize my young trees! I have always just thought for mature trees putting fertilizer on ground around it would make minimal impact. Agree with @FarmerDan that getting some concentrated fertilizer to deep roots might work. One of y’all figure that out for me!

Termite Ground Injection system...

 

[Angus 1895]

I think if you can get the nutrients below the root zone of the grass/ weeds you wi be AOK.

Nitrogen fixing legumes can be your friend.

To believe that nutrients supplement to an oak will not benefit acorns…….


is nutz

 

[bigboreblr]

If anyone does an experiment, I suggest you take pictures of acorn development. When a dry spell happened for me, the young flower/catkins would fall off. The couple of trees in my foodpot edge, I would water them and they wouldn't fall off.

Not scientific, or not recent. I recalled looking at the droopyness of the leaves. Sometimes I had 55 gal drums of water from previous rains. MY well wasn't great at that house, but used it to get a few trees by. IF you can get even a drum of water on a tree before its too bad, it'll get it by until more water comes. Some summers your screwed, but if you need a few good trees within bow range, its worth the effort.

IF you can water, do it.

Also, you can take a leaf blower and throw some leaves onto the base of some of your better trees.

 

[The Fishman]

I would tend to agree. It also doesn't mention there how they were able to both exclude animals from eating the acorns in order to measure increases in productivity while simultaneously monitoring depredation of acorns. And how many square meters were counted per tree? Which animals were eating the acorns? How was the area of the crown determined? Was the age of the trees considered? Was the data from the drought years thrown out or included? We're different kinds of fertilizer used? Was there a difference from site to site, or were the effects of treatment uniform across all locations?

There is a whole section in the materials and methods that discusses how they factored in depredation. They then discuss depredation in the results and discussion sections.

The materials and methods section discusses how production was measured on a per square meter canopy area.

Where are you getting drought years? The study doesn't mention drought years.

Ammonium sulfate was applied to the treatment sites. This was detailed in the materials and methods.

Each site within the general area is going to differ. This is why they had three different sites for replication and also to test for site differences within their model.

Not all of the materials and methods is presented since they direct readers to a previous paper that covered the initial 5 years of the study. The materials and methods within that paper provide additional information on some of your questions.

 

[The Fishman]

Well here's another issue I have with the study:

"We fertilized each tree in the fertilization treatments (F
and CRF treatments) with 168 kg/ha of actual nitrogen by applying
ammonium sulfate ((NH4)2SO4) around each tree. Application rates of
actual phosphorus (monocalcium phosphate; CaH4P2O8) and potassium
(potassium chloride; KCl) differed between sites and years based on soil
test results. We added enough phosphorus and potassium each year to
maintain 101 kg/ha of phosphorus and 269 kg/ha of potassium in the
soil (Savoy and Joines, 2009). We calculated the amount of fertilizer
needed for each tree by measuring the crown area (i.e., surface area
from the trunk of the tree to the edge of the crown) of each tree"

That sounds sloppy. It just adds a lot more variables. If they had added a single bag of triple 12 to each tree or each unit of area, I believe they would have gotten very different results. They applied the same amount of nitrogen to each tree but varied the P and K?

The more I read about this study the more skeptical I become of it.

Why would that sound sloppy? They did soil tests and standardized the phosphorus and potassium to limit possible variability amongst sites. Limiting the variability allows you to draw stronger conclusions on the variable that you testing which is how does nitrogen affect acorn production.

 

[The Fishman]

I will go out on a limb here. Soil fertility is not the limiting factor in production of acorns.

The researchers agree with you. They stated "These results provide further evidence that environmental conditions (i.e., weather) are the primary driver in masting cycles, and masting potential may not be primarily controlled by the availability of resources (i.e., light and nutrients). However, when environmental conditions do not constrain acorn production, individual white oak trees may be limited in production capacity by competition for light from surrounding trees."

 

[Telemark]

From the study:

"
Wolgast and Stout (1977) reported an increase in bear oak (Quercus
ilicifolia) acorn production following fertilization of young stands in
New Jersey. Callahan et al. (2008) and Bogdziewicz et al. (2017) re-
ported increased acorn production in small plots that contained red
oaks following 15 and 25 years of nitrogen additions, respectively "

 

[Telemark]

Where are you getting drought years?

"The Southeast region generally receives substantial precipitation and is often considered water-rich. However, droughts are not uncommon, and the Southeast has a long history of multi-year droughts, including the recently experienced record-breaking droughts of 2006–2008 and 2010–2012. Tennessee also experienced a high impact drought in 2016"

Tennessee

Current state-level drought information for Tennessee: .

www.drought.gov

That overlaps considerably with the years the study was conducted.

 

[omicron1792]

"The Southeast region generally receives substantial precipitation and is often considered water-rich. However, droughts are not uncommon, and the Southeast has a long history of multi-year droughts, including the recently experienced record-breaking droughts of 2006–2008 and 2010–2012. Tennessee also experienced a high impact drought in 2016"

Tennessee

Current state-level drought information for Tennessee: .

www.drought.gov

That overlaps considerably with the years the study was conducted.

I hear you.

It’s the best study ever performed in America on the subject. And likely the best that will be performed in our lifetime given tree time.

 

[Telemark]

Why would that sound sloppy? They did soil tests and standardized the phosphorus and potassium to limit possible variability amongst sites. Limiting the variability allows you to draw stronger conclusions on the variable that you testing which is how does nitrogen affect acorn production.

It's sloppy because it limits the ability to attribute P and K additions to increases in mast production. If they would have added the same amount per tree or the same amount per unit of canopy area, then it would have given a clearer comparison of how the added fertilizer affected mast production.

If you're comparing how added fertilizer affects acorn production, then standardize for the added fertilizer. They standardized P and K for soil concentration, but they standardized N for unit of area. They then used another variable, crown release, in the same study. That's sloppy.

I would like to see a study that compares changes in acorn production only between trees that receive fertilizer and trees that do not receive fertilizer. And the amount of all nutrients should be standardized the same way, either per tree or per unit of area.

Additionally, there should be discussion in the results regarding the effects of drought on mast production. It stands to reason that added fertilizer will have minimal effect if there is insufficient rain to carry that fertilizer to the roots of the trees being studied.

 

[Telemark]

Limiting the variability allows you to draw stronger conclusions on the variable that you testing which is how does nitrogen affect acorn production.

I don't think it was clear that they were specifically testing nitrogen fertilizer. The conclusions they draw make it sound like they determined fertilization in general does not affect acorn production.

Additionally, I don't understand why they wanted to test nitrogen specifically. If nitrogen is most beneficial to new growth, then it stands to reason they should have studied the affects of additional P and K instead of N.

Basically, the paper is a bit misleading in its conclusions. And if they specifically intended to only show the affect of nitrogen on acorn production, then the experiment doesn't really give me any helpful information at all, as I would never apply nitrogen specifically to encourage acorn production.

 

[FarmerDan]

Chase this one. The failure of an oak tree to produce acorns is closely related to the failure of oak tree flowers to complete the transition to fruit production and it's probably related to fungal disease within the flower at a critical time. The development of the disease is driven by many climatic features present in the spring. An oak tree is a complicated species. Fertilization might benefit the development of the tree. But it can't negate climate's impact on one small aspect of development.

 

[Brian662]

I can only speak for myself on this one, I won't ever attempt to fertilize an oak tree in an effort to increase acorn production.

 

[Telemark]

Chase this one. The failure of an oak tree to produce acorns is closely related to the failure of oak tree flowers to complete the transition to fruit production and it's probably related to fungal disease within the flower at a critical time. The development of the disease is driven by many climatic features present in the spring. An oak tree is a complicated species. Fertilization might benefit the development of the tree. But it can't negate climate.

It's an interesting concept to consider. If what you are saying is true, then the addition of nitrogen can be detrimental, while the addition K is beneficial.

"N negatively affects the plant’s physical defense along with the production of antimicrobial compounds"

"Potassium (K) is an essential plant nutrient, when it is present in adequate concentration, it can certainly increase the plant’s polyphenolic concentrations, which play a critical role in the defense mechanism"

Frontiers | Plant mineral nutrition and disease resistance: A significant linkage for sustainable crop protection

Complete and balanced nutrition has always been the first line of plant defense due to the direct involvement of mineral elements in plant protection. Minera...

www.frontiersin.org

"Nutrients like Phosphorus, Potassium, Manganese, Zinc, Boron and Silicon have been proven by research to boost plant immunity."

"Potassium and Boron strengthen the cell wall and cell structure which prevents fungi and other pathogens from entering the cell"

What can improve disease resistance in my crops? - Dhanashree Agro

Nutrients like Phosphorus, Potassium, Manganese, Zinc, Boron and Silicon have been proven by research to boost plant immunity. Similarly Salicylic Acid and Jasmonic Acid play an active role in defending the plant against pathogens. Phosphorus is responsible for root development, a healthy root...

dhanashreecropsolutions.com

 

[BuckSutherland]

I kinda skimmed through the thread. Here is my take on fertilizing oak.

1. I am only doing it to young trees that I just planted or are less than 4 years old. Combine this with a GOOD weed mat and some mulch and they take right off.
2. It really helps getting the young trees growing. I'm not that worried about older trees. They are in God's hands.
3. Cutting down their competition will help them immensely. The sun is a powerful thing.
4. There is no way in hell to have an accurate study UNLESS you took acorn size and weight into consideration. I plant my corn at much lower population than my neighbors. We end up getting similar yields. Their kernel size is way smaller than mine. Same could be true for acorns.
5. Highly unlikely that it would be cost effective to fertilize oaks for more/bigger acorns. Better to stick with the small ones. They really respond.
6. If you wanna get some fertilizer in the ground pick up the shovel and make a slot, throw in some triple 19 at 10-12" deep and reclose the hole. I do it all the time. It goes quick on young trees. I try to place it approximately 16" from the central leader. You wanna promote the root growth to find the fertilizer and also dont want it too hot in closer to the leader.

 

[The Fishman]

"The Southeast region generally receives substantial precipitation and is often considered water-rich. However, droughts are not uncommon, and the Southeast has a long history of multi-year droughts, including the recently experienced record-breaking droughts of 2006–2008 and 2010–2012. Tennessee also experienced a high impact drought in 2016"

Tennessee

Current state-level drought information for Tennessee: .

www.drought.gov

That overlaps considerably with the years the study was conducted.

Go to https://droughtmonitor.unl.edu/Maps/MapArchive.aspx and please let me know if the study area was impacted beyond an abnormally dry period for more than a month during the study time period. The study ended in 2015, so I am not sure why a high impact drought in 2016 is relevant.