Potassium a problem for Hugelkultur?

@William James
You don't have to use rock dusts if you don't want. If your soil have copper deficiency add copper sulfate. If you have sulfur deficiency add sulfur, or gypsum, if selenium use sodium selenate, if phosphorus add MAP, if potassium add potassium sulfate... It's more practical. I've written a whole post about it:
http://designerecosystems.com/2014/08/15/how-to-get-the-benefits-from-rock-dust-fertilizer-without-hauling-tons-of-material/

You have a great point, that you noticed that Geoff Lawton uses compost and manure that is enriched in minerals. It's one aspect of why it work. In similar way people will say that Joel Salatin's system is so great because he uses rotation grazing, and if you do that you don't need to fertilize your pastures. But why not count the nutrients from the chicken feed and pig feed that he buys? The nutrients he is adding to his pastures come from unsustainable sources.

Let's imagine a perfectly balanced soil. Now let's add tons of potassium to it. Will the plants suddenly be deficient in phosphorus and other minerals? I think not, because the soil organisms can unlock minerals tied up by imbalances. Of course, if there is no phosphorus, that is a different question, and you need to get phosphorus from somewhere.

Here is an actual experiment, showing that deep woody high potassium mulch actually balances soil minerals. Here is a link. http://www.waldeneffect.org/blog/Do_wood_and_straw_raise_soil_potassium_levels__63__/

And this writer likes Solomon's book, and understands the importance of nutrient dense foods.

@Gilbert Fritz,

We don't have to imagine anything. The studies had been done. Your example with phosphorus and potassium is not ideal, as potassium is a cation and phosphorus is an anion.

If potassium is abundant in the soil (above 3-4% Base Saturation) it will be taken up by a plant in higher amount. The plant will not take a lot of calcium, and calcium is the nutrient that is needed for plants to uptake other nutrients.

And I want to say there are shades of gray of that... For example tomatoes you can buy in supermarket are fertilized with high amount of potassium. They are growing, but they are tasteless and not nutrient dense.

Her hypothesis is flawed (the nutrient balancing aspect of wood). Why?
She added not only wood, but other products (horse manure) so it can't be a good estimation of how (only) woods. Horses are usually fed a lot of supplements, to balance minerals in they diet, so the increase fertility (micronutrients) is caused by addition of imported, somehow "balance" horse manure.

Check the ratios between phosphorus, zinc and copper. Her soil is not getting "more balanced" in this respect. If she knock out a bit of potassium, add zinc, copper, boron she will get great results.

Wojciech Majda wrote:@Peter Ellis
Putting back minerals into the soil is not going to damage ecosystems.

Hi Wojciech,
I don't want to put words in Peter's mouth, but I think what he is referring to is the damage to ecosystems caused by the extraction of minerals. The minerals one puts in one's garden come from mountains that get holes bored into them. Whole mountains have disappeared (even one near me) for the construction industry. Beautiful alpine ecosystems become not-as-beautiful cement homes. It wouldn't be wise to base a long term and widespread agricultural strategy on these extractive industries, no matter the benefit to human health.

William

@Wojciech
I did some cursory research, and I am still unconvinced that minerals like sulfur, gypsum, calcium can be obtained from sources that are sustainable. Some alternatives to mining do exist, but they usually are the byproduct of other nasty industrial processes. For example, Flue Gas Desulfurization produces sulfer but comes from electric power plant scrubbers. Potentially better than mined material, but hardly sustainable.

If you have some information to share that would sway me in another direction, I'm all ears. I'm always on the lookout for better sources for soil nutrients.

Oh, for the record I did a soil test and my potassium levels were above normal and everything else was low. I use straw as a primary mulch material. I've lessened the use of it since.

Thanks,
William

Hi Wojciech,

I think the reasoning behind her experiment is that Solomon says that manure, chips, logs, and straw/hay all contain too much potassium. Also, Solomon says that too much potassium means that plants will not get enough phosphorus, I am not sure why.

Gilbert Fritz wrote:ìSolomon says that too much potassium means that plants will not get enough phosphorus, I am not sure why.

Following Solomon's logic, when nutrients are unbalanced, excesses of certain nutrients can cause deficiencies in others. It isn't a problem of the nutrient not being in the soil, but the bio-availability of that nutrient. It's a variation on the Cation Exchange Capacity (CEC) of Albrecht. Some soil testing labs give you your nutrients with the correct balances following the logic of CEC.

William

Wojciech Majda wrote:
You have a great point, that you noticed that Geoff Lawton uses compost and manure that is enriched in minerals. It's one aspect of why it work. In similar way people will say that Joel Salatin's system is so great because he uses rotation grazing, and if you do that you don't need to fertilize your pastures. But why not count the nutrients from the chicken feed and pig feed that he buys? The nutrients he is adding to his pastures come from unsustainable sources.

Hi Wojciech,
That's a good question. I personally wouldn't count the chicken feed that he buys as being unsustainable for two reasons:
1) Geoff is currently working without adding chicken feed with some of his chickens. He has a composting chicken tractor that only uses kitchen waste, manure, and straw.
2) Feed is something that often comes from unsustainable sources, but in theory could come from sustainable sources, if the infrastructure exists around you. Not so with mined or industry-dependent sourced materials.

William

@William
I didn't mean it in a way, that mining thous nutrients will not damage ecosystems. It does, and i don't think there is a way around it (except using uncontaminated humanure, before it is mixed with water contaminated with heavy metals from our streets). The solution is to rehabilitate the place after the use - maybe turning a place into a nice lake, dam... Possibilities are limitless. It won't be the same, but it doesn't have to be bad.

What I wanted to say, is the fact, that adding nutrients (in the right amount and right way) will not damage that ecosystem (or soil biology). To the contrary - it will enhance it.

We have a difference of opinions her - for me number 1. is human nutrition, so if it means I need to use industrial products, I will use them. Considering, that the stuff is being used for silly stuff anyway... It's the same story as with using fossil fuels - unsustainable, but beneficial in the current system.

@William

I was referring to Joel Salatin. Geoff, do not produce on a commercial scale. I think the eggs that chickens and ducks on his farm produce, are being eaten by students, so there is a close loop system. That's not what's happening on Polyface farm, so he has to import chicken feed AND minerals for his chickens... Otherwise he would not be able to produce a lot of chicken eggs and broilers as his soil would not be able to produce enough high quality food. It is not a surprise, as his farm is in a relative rainy place. Place that soil do not have a lot of minerals in the soil, as they were leeched out by rain...

You may also wish to look at availability and rate of release.
In the past, ground rock phosphate itself has been used as a source of P for acid soils. However, due to low availability of P in this native material, high transportation costs, and small crop responses, very little rock phosphate is currently used in agriculture.

If you are adding phosphate every year would it not be worth thinking of adding a source with a low availability?

The same goes for many other minerals. Should we allow natural weathering to release nutrients?

Solomon's point about animal biomass being lower in forests versus prairies is incorrect if soil macroinvertebrates and the fish at the bottom layer of any healthy forest are considered.

I've changed my mind about this topic since I started posting; I think Steve Solomon is mostly right. However, even Steve himself is now a little less worried about excess potassium. But he is right that just stimulating microbiology will not in and of itself yield nutrient dense food. Also, adding a balance of minerals will stimulate microbial life. For instance, in a high magnesium or potassium soil, the soil will tend to pack tight and exclude air. Calcium helps air and water balance in the soil, to the great benefit of soil life.

As far as the Sustainability of adding minerals; they would only need to be added for a few years, IF there was a closed loop system. Importing materials, growing plants, eating plants, and flushing the minerals down a river into the ocean is unsustainable. Importing minerals once and then cycling them forever is sustainable. Permaculture setups should not include flush toilets, exported produce (at lest to a great distance), or soil erosion, so whatever you add on site will stay there for thousands of years.

Also, about the argument that we can't focus on the highest possible level of human health, but instead must focus on a healthy ecosystem; I suspect that if humans in a system are not healthy, other aspects of the system are also unhealthy. By working to grow optimally nutritious foods, we will probably achieve a high level of health in the ecosystem.

There is a tendency in the world to separate and oppose humans and Nature. Really, we humans are part of nature; we are not a separate, alien curse or scourge. Therefore we can be healthy parts of a healthy system; there is no either or. We are not parasites.

I would again point out that in my reading of Solomon's work and many of your interpretations, along with Western civilization, seems to fail to appreciate the value of anadronmous fish in returning nutrients to our soils. I understand the main components of salmon meal to be phosphorus and nitrogen along with a good amount of C, Mg and many other micronutrients. Exactly what Solomon claims we are missing. I do wonder what he would say about kelp and seaweed. I just get the feeling Solomon is always selling something to replace what you can get yourself.

Steve Solomon's COF contains seaweed, and can contain fishmeal. I'm not sure what you mean by selling; if anything he is selling information.

Solomon has definitely sold some goods in addition to information in his time, though I can't spite him for that. What does "COF" mean? In regard to "selling something" mainly meant that he seemed to argue that the only way to get the food he defined as nutritious was by buying or importing nutrients that seem to also require mining. I guess I may be ignorant about home rock grinding processes though. I did not read everything he's written, and he may be right. He has undoubtedly grown more plants than I have. However, it seems to be hard to imagine how the ocean would lack any mineral that occurs on the Earth's crust. Ocean plants and animals that occur in blooms of abundance will often be accumulating the runoff of eroded soils, and this is largely what is being depleted. That or they are fed by upwelling of diverse nutrients from the ocean floor. The soils growing the largest forests on earth also contained the largest salmon runs for a reason, and this runs both ways (pun intended).