Help me interpret my soil test results

Hello all, I just got my soil test results back from Logan Labs and I would appreciate whatever help I can get in interpreting the results, and perhaps some ideas for the best ways to make improvements based off these results.
I have attached my results. I am on 1.5 acres on the Mornington Peninsula, Victoria, Australia.

I took 3 samples:
1) the first sample ("West") is top soil at the highest elevation of my block which is on the west side
2) the second sample ("East Top") is top soil from the lowest part of my block which is on the east side.
3) the third sample ("East Sub") is the clay sub soil from the lowest part of my block which is on the east side.

I have just read The Intelligent Gardener so my observations are largely based off what I have learnt there.
My observations:

Sample 1 - A reasonable light (lowish TCEC) and very acidic soil, as I already knew from home testing. Magnesium levels look fine, so mostly looks like I need to add quite a bit of lime to fix pH. Also seems to be like a lot of other imbalances, like very low P, low K, and a lot of Fe.

Sample 2 - TCEC 3 times as high as sample 1 and OM% high as well as I'd expected from looking at the soil. Also very acidic, with magnesium being a bit on the high side, and calcium really lacking. This low part of the block is close to an estuary, about 1km inland from the sea, which get's very wet when we have a lot of rain. I am guessing this is the reason the sodium levels here are so high. Any strategies I can use to make this area productive? Could I make raised or mounded garden beds and hope the sodium will eventually be flushed out, or will it continually wick back up into the soil?

Sample 3 - As mentioned, this is the clay subsoil that is about 1m below in the same area as sample 2. I had been hoping to see a high TCEC in this clay so I could dig some up for use else where, but doesn't appear to be the case.


Another question - My iron levels are apparently very high, is that because iron is very available in low pH soils like mine, and will this be remedied by bringing the pH to a more appropriate level?

Please let me know your thoughts and what actions you would take. Thank you

Hi Bowen-

After looking over your soil test results, I think you’ve got some decent soil here to work with, but some amendments are needed in order to have healthy garden plants and successful crops.

Lime is certainly needed for the West and East areas, and don’t use dolomite lime, it contains magnesium, which the soil doesn’t need more of. If you’re planning to grow plants that require acidic soils, like blueberry for example, I myself would leave an area in the East section unlimed for those. Lime your soils and aim for a target pH of 6.5. After liming, the soils may still could use some more calcium, and add gypsum to get that calcium without altering the pH. If you do decide to leave an area unlimed for acid loving plants, add extra gypsum in that area to get the calcium needed there.

The soils definitely need phosphorous, consider soft rock phosphates as a source.

Boron and Copper are low, add boron with a target of 2ppm, and avoid going over 4ppm. Add copper with a target of 5ppm.

Your question about the iron being high in the test, that is not a result of the soils pH. Soil test extraction methods are going to show, in this case, all of the iron in the soil. Low pH’s only means more of that iron is available for use for plants grown in that soil. I wouldn’t worry about the iron.

I also wouldn’t worry about the high sodium in the East sample, and here’s why. The sodium cation has the weakest bond of all the cations. When you start liming this soil for instance, some of the calcium in the lime is going to displace and knock off some sodium cations, which can become mobile and flush on out of the soil with rain.

My suggestion is to lime, then add phosphorous, but not these two at the same time. If done at the same time, the calcium and phosphorous can bond together instead of individually doing their thing in the soil which is what you want. Consider adding a little boron and copper, maybe even a little zinc but that’s not high on the priority list at this time. Try getting these amendments in this year and then retest the soil next spring and see how ya did.

Bowen Rees wrote:

I took 3 samples:
1) the first sample ("West") is top soil at the highest elevation of my block which is on the west side
2) the second sample ("East Top") is top soil from the lowest part of my block which is on the east side.
3) the third sample ("East Sub") is the clay sub soil from the lowest part of my block which is on the east side.

James gave you good info on your soil tests results.

I'm going to talk a bit about your sampling method.
It makes no sense to take only one area's top horizon and the accompanying second horizon (sub soil), that one area gives you all the results you would want for that area.
I have to wonder why you didn't take the second sample from the West section, which would have given you all the info you should have for making best fit amendments for that area.

sampling soil for testing for the purpose of gardening or farming is usually done around the 12-18 inch level.
My preferred sampling method is done with a 1" metal pipe sampler that is marked at 6" intervals. You just drive it down and then use a push rod to remove the sample.
This way you can record not only where but exactly how deep a plug the soil represents, which gives you better data to use for amendments, you can also use a tape measure and separate the plug into each horizon by color.

Thanks James and Bryant, I really appreciate your help!

Interesting thoughts about the sodium, hopefully you are right.

A couple more questions:

I was wondering what is a good way to apply the lime; i.e. for sample 2 area, say I need to add 1.4kg of ag lime per sq metre, and 200g SRP per sq metre, how would you recommend applying it? Should I spread the full dose of lime on the surface all at once or do it in batches (that would be far more labour intensive)? And how long to wait before adding the SRP after applying the lime, I have read between 3-6 months from different sources, I obviously don’t want to waste the SRP as it’s reasonably pricey?

Is putting wood chips over the top of the applied lime beneficial in anyway (maybe stop it blowing away in the wind and keeping the soil moist might speed up integration into the soil), as I have a lot of wood-chips piled up atm?

Cheers,
Bowen

hau Bowen,  I like to do a minimum of two applications when using lime. Spread 1/2 the needed quantity and gently water this in. Wait a few days before spreading the second application.

I would get the lime into the soil prior to using the SRP, that way the soil will be better able to adsorb the SRP.

If you are going to use wood chips, I would lay down all the lime evenly and cover with 2 inches of wood chips as I went along, that way you have the lime covered against wind blow losses.
Once you are done with the application, water the area well, the wood chips will break the impact of the water thus allowing the lime to wet evenly and begin soaking into the soil.
This will also reduce leaching effects of rains.

Redhawk

Hi Bowen,

Just to let you know the download of the report is not working.

Cheers
Tony

I really recommend watching all 9 of the videos from this 2 day workshop. One of them (#2 or 3 I think) is all about reading your soil test and how to figure out how much you need to add of amendments to the soil. I'm math challenged and he made it easy enough for me to do the math.

https://youtu.be/_4HQamNJIMo