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My soil test results (high in organic matter, low in minerals/low pH)  RSS feed

 
Tony Flint
Posts: 27
Location: Maple Valley, WA, USA - Zone 8a, 500 ft elevation
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I had Logan Labs perform a soils test for the pastured areas on my farm, and here are the results (pdf):



I have just begun to interpret these results, and I'd welcome any opinions - I am an absolute beginner when it comes to soil testing/intervention.

Context: I just moved out here last summer, and from what I can tell the pasture could be a lot more productive/diverse; there is a lot of moss and not many distinct species extant in the pasture. That said, this is also my first farm and I have no idea what I'm doing. I grew my first garden last year with the help of Steve Solomon's "Growing Vegetables West of the Cascades". I raised and slaughtered four goats and three pigs, and have 23 hens racing around the pasture in their Chicken Ferrari paddock shift system. My goals are to increase the health and fertility of the soil generally, and to promote biomass creation and engender diversity. I am still in the phase of learning, both in how to observe the ecology and what options are available for promoting its succession to a higher level of productivity (goals include growing most of the food for me and the livestock, and managing better the seasonal streams that currently race across the property).

A couple of attachments:
1. A topo map overlaid with the sample locations - I have access to the six parcels from which the samples were taken. Ignore parcel #9099; I was trying to lease it but it was sold and I will not be able to use it;
2. An overlay of the NRCS Web Soil Survey map, mainly comprised of the following two types of soils which I sampled separately:
Sample A (AgC/AgD on soil map): Alderwood gravelly sandy loam, a "moderately well drained gravelly ashy sandy loam" (full details here)
Sample B (RdC on soil map): Ragnar-Indianola association, a "well drained ashy fine sandy loam" (full details here)

Easily accessible free inputs:
Knowledge (i.e. permies' wisdom);
Wood chips;
Espresso grounds (this is near Seattle, after all);
Cardboard.
Sample_Locations.jpg
[Thumbnail for Sample_Locations.jpg]
Soil sample locations
Soil_Map.png
[Thumbnail for Soil_Map.png]
NRCS Web Soil Survey
 
Tony Flint
Posts: 27
Location: Maple Valley, WA, USA - Zone 8a, 500 ft elevation
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Initial observations:

- Organic matter seems high;
- pH seems low;
- There appears to be a deficiency of most minerals.

When thinking about the 'weakest links', there are several candidates. There are minerals in which the soil seems nearly bankrupt: sulfur, boron, and copper. Calcium too seems significantly deficient.

Brainstorming list of unqualified ideas:
1. Continue paddock shifting of chickens;
2. Add ruminants;
3. Add rabbits;
4. Ritual sacrifice of one or more of the above;
5. Add some/none/all of: Lime, Boron, sulfur, Bio-char, compost, wood chips;
6. Begin plans to better manage water in order to prevent leaching and to capture minerals/nutrients;
7. Move to another farm.

Current Plan:
A. Read some more Albrecht/Solomon;
B. See how much it would cost to lime the pastures;
C. Make a better plan.
 
Leila Rich
steward
Posts: 3999
Location: Wellington, New Zealand. Temperate, coastal, sandy, windy,
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Tony, I'm not the best at reading soil tests and yours is in American...
In NZ, a standard lab test includes carbon levels.
I can't see it there? Carbon (or rather lack of it) is a really big problem here.

That organic matter is pretty damned high-are you confident that your samples didn't include fresh compost etc?
It's also pretty acidic, which could explain some of your low mineral numbers-see Liebig's_law_

I'm also curious about the widely varying numbers between sample A and B.
Maybe it's the unfamiliar testing, but I'd generally expect minerals to be reasonably similar in adjacent areas.
I'd say "synthetic fertilisers", except your sample's numbers see-saw, and I'd expect one to be consistently higher.

If your mineral numbers are low because they just are, it quite possibly means they're low for a long way around you,
and anything you grow or bring in from your area (including animals) will also be deficient.


 
John Elliott
pollinator
Posts: 2392
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One thing that stands out is the low level of boron. This is not surprising, since boron is quite leachable and you are in a soggy area. I make it a practice to incorporate boron by adding boric acid to my (almost) daily batch of compost tea. I've explained it a little more in this thread.

As for the other minerals, you might consider incorporating rock dust for a while, at least until it brings up the levels of minerals.
 
Tony Flint
Posts: 27
Location: Maple Valley, WA, USA - Zone 8a, 500 ft elevation
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Thanks for the input!

Leila, this is my first soil test, so I'm not sure! I haven't heard of carbon deficiency being a problem here. I followed the instructions provided by the testing lab: remove sod, dig a 7" deep hole, get a good 'slice' of soil with a shovel, and cut out the center inch from the blade from the surface edge to 7 inches deep. It seemed to work pretty well. I'm the only one who would have added amendments to this land, so I feel confident that no contamination took place.

John, thank you. I'm going to add some boron - see the plan below.

Here's the plan I'm implementing specifically for my ~1000 square foot vegetable garden. I'll figure out what to do (probably something similar) for my pastures. Sharing my math so it can be laughed at and/or hopefully help someone else (and probably me in the future - that's one fun thing about being absent-minded/forgetful).

1. Soil test results show a pH of 5.3 - these soil tests were taken in the same type of soil that the garden has, but did NOT include soil from the garden;
2. According to this, I should add '78 pounds of limestone to raise your soil pH to 6.5 - 6.8';
3. According to Paul, I should 'Apply 25 pounds of lime per 1000 square feet. At least a month later, add another 20 pounds of lime per square feet.';
4. I added roughly 75 pounds of a mix of half agricultural lime / half dolomitic lime in 2013. This mix was ~75% calcium / ~25% magnesium, so ~56# calcium / 19# Magnesium;
5. This should have brought my pH in the garden up to ~6.3 (56 [applied] / 78 [from #2] = 0.717 * 1.45 [halfway between 6.5-6.8 - 5.3] = 1.04 + 5.3 = 6.3);
6. I estimate that ~25% of these minerals have leached out during the winter rains, that means it is as if I applied 42# in 2013 = pH of 6.08 using same math;
7. Deficiency reported in soil test results show a ~75/25 Ca/Mg deficiency, which is convenient as it matches the mix from #4;
8. According to #2, I should add 35 pounds of limestone to achieve 6.5-6.8 pH;
9. Lime weighs 80# per cubic foot = 2.66# per quart = ~13 quarts;
10. According to #3, too much at once could be toxic, so I'm going to apply 20 pounds = 7.5 quarts;
11. To achieve 20# lime / 5# Mg, I will create a mix of 12.5# (4.7 quarts) Agricultural lime / 12.5# (4.7 quarts) Dolomitic lime;
12. According to this, I'll add 0.5oz of Boraxo to the mix from #11;

Cheers,
Tony
 
Tony Flint
Posts: 27
Location: Maple Valley, WA, USA - Zone 8a, 500 ft elevation
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Follow up:

My Agricultural/dolomitic lime were not the same density, being crushed to a different particle size. The agricultural lime was ~3.1#/quart while the dolomitic lime was ~2.1#/quart. I mixed the specified weights together and top dressed this over my raised beds, then hoed it in to the top inch or two of soil. Next up: consider amending other deficiencies (copper, sulfur) and evaluate plant health/production throughout the season.
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