Fig fertilizer study - Attention Pete

[HarveyC]

Last September or so I had an agronomist I hired for my chestnut orchard nutrition program check the soil in my fig orchard. I had noticed that several varieties had fruits that took forever to ripen or which never ripened at all. The test revealed it was very low in potassium. This area had previously been planted to alfalfa which apparently depleted the potassium. Potassium is particularly important for fruit formation so I was trying to find some recommendations for fertilizing figs with some specific studies instead of some of the common "shoot from the hip" sort of recommendations that seem to be so common.

I came across this somewhat dated report from Brazil which I thought was very good. It covers more than figs but the first fruit covered is figs. http://cdn.intechopen.com/pdfs-wm/41134.pdf I'm thinking of putting on about 60 grams of K2O per tree this year, probably in the form of potassium nitrate (different grades available, about 13-0-44), split over 3-4 months, injected through drip. I would probably put a higher dose the first month because of the deficient condition.

Pete, you've got an analytical mind and I'd appreciate your thoughts.

[AscPete]

Harvey,
I haven't yet had a chance to read your linked document but I've attached a few recommended fertilizer ratios for fig production and a Spanish document for application of fertilizer for figs.

Pierre Baud, http://www.fig-baud.com/pageanglaise.html
7-3-7 for vegetative growth with
6-3-10 for fig growth and development
4-8-12 or 10-20-25 for "well balanced soils"

Japanese Commercial fig Production, http://www.hawaiifruit.net/Figs-Japan.htm
10-8-10 for normal production
14-10-7 for trees 25 years and older.

http://www.ivia.es/sdta/pdf/revista/...s/17tema22.pdf

I don't know much about large scale farm fertilization, but getting your Potassium levels back up to a better "range" will only help with the overall health and growth of your trees since its critical to many other plant functions than fruit / flower production.


After quickly reading the document one important item is almost missing and never actually mentioned, the pH of the soils.
As you know nutrient availability is governed by the soil's pH, in the table on page 5 they show a before and after pH value of 4.5 and 5.6. IMO, The lower pH values will decrease the availability of Macro Nutrients and skew test results. http://extension.umass.edu/landscape...nt-ornamentals

[AscPete]

Add broken link to 17tema22.pdf document...

https://www.ourfigs.com/filedata/fetch?id=94735

[HarveyC]

My soil pH is fine at at 6.5. Nitrogen level is "adequate" and phosphorus level is moderately high.

[HarveyC]

I don't care for any of the general fertilizer guidelines because they don't take into account soil composition. I have no desire to add phosphorus, for instance, since it is already high.

[AscPete]

Harvey,

The fertilizer guidelines can be used as a reference point.
You could get the levels of Potassium back up to a normal range and then maintain a "balance" closer to one of the guidelines...

For example the The Japanese Commercial fig Orchard prescriptive fertilizer schedule for in ground Espaliered trees is a 8-7-7 Organic fertilizer (a ratio of 1-1-1) with an added boost of Potassium Sulfate (0-0-50) when the figs are at the stagnant stage.
The indicated season is from April to October with the Potassium applied in July. They start with prepared soil with average fertility and pH adjusted to 7.2 ~ 7.5

Although its in Japanese the schedule is on page 16 of the attached Prescriptive Commercial Fig Orchard manual. It shows the application of fertilizer for 1st Year, 2nd Year and 3rd Plus Years.

[HarveyC]

I'm working with an agronomist from a Spanish-based country that works in 20 countries and he suggests a pH of 6.5. As shown in the nutrient availability chart above (something I first became familiar with in a Soil Science class a very long time ago (around 1976), this provides good availability for all nutrients. This company has the largest orchard growers in the state among its clients and they do some very impressive consulting work. I'm not using them extensively for my figs yet since I can't justify that as I'm not even selling fruit yet (I am using them for my chestnut orchard this year).

The subject of my original post was targeting the discussion of potassium specifically. Both because of my delayed fruit development in my new orchard which is located on soil which is potassium deficient. The study linked in the OP is particularly good, IMO, as it specifically shows the effects of plant growth and fruit production at different potassium levels.

As far as using general fertilizers such as recommended on some other studies, I don't believe I'll likely use them. I doubt I will ever need to add phosphorus to my fig orchard in my lifetime.

[AscPete]

I completely agree with maintaining a pH of 6 ~ 7 and have advocated for that range in the Past.
http://figs4funforum.websitetoolbox....3&postcount=20

As mentioned in the link above I practice some sustainable Organic Gardening which differs from most Commercial Farming practice. In Organic Gardening soil health, structure and microbes are cultivated while in Commercial Farming soil fertility is measured and ammended to produce the largest harvest. Organic Gardening adds compost,manures and cover crops to put plant matter back into the soil for the needed nutrients while most Commercial Farming usually removes the plant matter (chemically and or mechanically) and adds fertilizers to replace lost nutrients.

http://www.mgofmc.org/docs/nutrientdeficiency.pdf ,

A rule of thumb for gardeners is that if plant matter (leaves, branches, grass clippings, weeds, etc.) are removed from a site, something needs to be put back to replace those lost nutrients.

My experience has been that healthiest growth of my potted fig trees occur within that pH range (pH 6 ~ 7). I provide the needed balanced fertilizers and soil microbes because they are being grown in essentially a sterile medium, and the 2-1-2 NPK ratio has produced consistently good results...

IMO, The Document in your OP has a major error in the methodology and conclusions due to the simple fact of the low pH values.

[HarveyC]

I use cover crops in my chestnut, pom, and fig orchards, FWIW. Many other commercial farms do as well. My farm is located on former swamplands and microbial activity is high.

I wondered about the low pH in the study but noted that they at least increased the pH from 4.2 to 5.6 where potassium still has fairly good availability. This study is valuable in that it specifically measures plant and fruit production at various K levels.

[AscPete]

Its great to know that more farmers are practicing Sustainable Farming...

As a reference / comparison the Japanese document prescribes topdressing an additional 65 grams of Potassium Sulfate (0-0-50) for 1 - 3 year old trees and 130 grams of Potassium for trees 4 years and older.

The numbers are extrapolated from the document, they plant 150 (151) trees in ~ 1/4 acre (10 ares), the trees are thinned in year 4 to 75 trees, with an application of 10 kg / 10 ares, it works out to 65 and 130 grams respectively.

[paully22]

Harvey you got me thinking. I have for the last 3 years started the season with fruiting kind of fertilizer. I do get more brebas and tons of main crop figs. I believe if I protect my brebas from the cold nights till late May, I will have a better crop.

[AscPete]

Harvey C,

Any updates as to your Potassium application rates, pH and condition of the plants in the Fig Orchard?
Also any idea of the final NPK ratio or analysis of the orchard's soil?

Thanks.

[HarveyC]

No, not yet. I decided to use the agronomist/lab that I'm already using for my chestnut orchard and he installed two isometers in my fig orchard a little over a week ago and my first samples of soil solution (from 20cm and 40cm) and leaf samples were sent in to the lab on Thursday. This is not cheap. There does not appear to be any phenology models established for figs and establishing one is way beyond my budget, but we can still get a pretty good idea with growth assessment and tissue analysis.

This firm has many of the largest growers in the state as their clients and they generally shoot for a soil solution pH of 6.5.

I'm looking into a sulfuric acid injector for my chestnut orchard (the largest provider of such services told me on Friday that it would probably cost $6-7,000 for the equipment, the sulfuric acid is relatively inexpensive but hazardous). I put this system in place I may see if I can figure out a way to add my fig orchard irrigation onto my chestnut orchard. Much to investigate still.

Tomorrow I'm hoping to put foliar sprays of zinc and copper on my chestnut orchard and will probably do the same for my figs but will await the testing results and the agronomist's recommendations which should arrive in about a week.

[AscPete]

Harvey,
Thanks for the reply...

[sal]

AscPete

Is the only reliable test to soak a given Media/Soil and measure runoff PH? I know that's what they do in the Hydroponic Community. I only have seen the cheap test kits for PH of solids.

[AscPete]

Yes, its simple, repeatable, reliable and the standard means of measure, http://www.epa.gov/region9/qa/pdfs/9045_1crf.pdf , or http://www.epa.gov/osw/hazard/testme...pdfs/9045d.pdf
Since roots need moisture to absorb nutrients from the "soil" the pH of the wet root environment (and dissolved nutrients) is the criteria.

[sal]

Whats a neutral type of water to use distilled?

[AscPete]

Yes, also check its pH before use...

[flashes23]

AscPete

I've read over many of your comments, and they are a wealth of information! Thank you for all you do. I do have a particular question if you don't mind. I have no ability to soil test at the moment for a multitude of reasons. I have 2 in ground figs that are about 3-4 years old. They produce fruit, last season had a very thick skin and were particularly dry. Is there a certain fertilizer that I can add to the soil to help? I have 9 cuttings that will be placed in pots soon, and I will follow your guidelines for those. I know its difficult without knowing exactly what the soil lacks, but are there some things like the Alaskan Fish, or Espoma products that I can add that will not harm and may help? Thanks for your time.

[AscPete]

For in-Ground trees the recommended is a nitrogen fertilizer approx. 10-10-10, but most in-ground trees in my zone 6 - 7 usually are ok with just compost and adequate water. Your location would dictate best practice with soil tests providing the best course for adding nutrients or supplements as needed. In my experience along with adequate water in-ground trees usually only require some added Nitrogen. Used in moderation Alaska fish or Espoma would be fine as fertilizer / Nitrogen source.

As mentioned for potted culture complete fertilizer with macro and micro nutrients is the best option for healthiest growth. Good luck.

[YATAMA]

Harvey, I secnd the motion on K. Here ca get 0-0-50or0-0-60 the 60 9s much cheaoer but is KCL and Cl is plant ufriendly/. applyig lot of K helped my vineyard immensely. Also ading B helped lot as soil here had zero, also Zn folar applications helped my prunes a real lot as was low in soil and apparently soil Zn appications are not as good as the folair spray which also does good if doemantbark is wet well with Znsprays.CA AG guys had lot goodinfofor me on this stuff!