# Low K and Mg



## liamjones (Apr 29, 2020)

Results of my latest soil test result, october last year vs (May last year in brackets)

CEC: 9.3meq/100g (12.9)
PH: 6.7 (6.7)
P: 26mg/l (33)
K: 69mg/l (194)
Mag: 99mg/l (79)
Calcium: 1409mg/l (1879)
Sulphur: 12mg/l (72)
Zinc: 18 mg/l (21.9)
Manganese: 33mg/l (22)
Copper: 5.4mg/l (5.5)
Iron: 617mg/l (575)
Boron: 1.17mg/l (1.26)
Sodium 38mg/l (45)
Molybdenum: 0.03mg/l (0.01)

Last year i only fertilized N and Fe.

This year i plan on fertilizing the following per month


N: 1 lb/k to meet demand

K: 1 lb/k to meet demand and raise levels

Mg: 1 lb/k to decrease current Ca:Mg ratio of 14:1 and keep up with increasing K, therefore maintaining K:Mg ratio of about 0.7:1

Fe: 1 oz/k to meet demand

I have already this month applied a 8:12:8 + 3 Mg as i had it laying around giving me:


N: 0.66 lb/k

P: 1 lb/k

K: 0.66 lb/k

Mg: 0.25 lb/k

I plan on ordering a 12:0:12 + 3 Mg + 2 Fe giving me per month:


N: 1 lb/k

K: 1 lb/k

Mg: 0.25 lb/k

Fe: 0.16 lb/k or 2.5 oz/k (way more than my normal 1 oz/k foliar apps)

I'll then supplement 10% Mg Epsom salts giving me an additional per month:


Mg: 0.75 lb/k

Firstly, have i read my soil test right and identified the ammendants i should make?
Secondly, does my approach sound sensible? Or is there another approach i could take? I considered carrying on with foliar urea and then granular SOP and Epsom, but would like to try out a granular N so might as well get a pre-mixed fert as proposed aboved.


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## Virginiagal (Apr 24, 2017)

No one has replied yet so I'm going to, just so you won't think we're ignoring you, even though I don't have anything really useful to say. We don't know what lab did the tests, what extractants were used, what recommendations the lab made. I suggest you do whatever the lab recommended. I don't think ratios matter much, as long as there are sufficient nutrients.


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## ABC123 (Jul 14, 2017)

I would apply ammonium sulfate fertilizer (21-0-0). AMS is 24% sulfur.

I would also apply epsom salt 3 times a year at 2lb/m

You could also use a balance fertilizer.


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## liamjones (Apr 29, 2020)

Virginiagal said:


> No one has replied yet so I'm going to, just so you won't think we're ignoring you, even though I don't have anything really useful to say. We don't know what lab did the tests, what extractants were used, what recommendations the lab made. I suggest you do whatever the lab recommended. I don't think ratios matter much, as long as there are sufficient nutrients.


Haha, thanks, im in the UK, so knowing the lab wont be helpfull, however, this is a link to the test https://www.pitchcare.com/shop/soil-analysis-broad-spectrum-cec-500g.html

i don't know what extractants were used, the lab made no recomendations, they just provide the results.


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## liamjones (Apr 29, 2020)

ABC123 said:


> I would apply ammonium sulfate fertilizer (21-0-0). AMS is 24% sulfur.
> 
> I would also apply epsom salt 3 times a year at 2lb/m
> 
> You could also use a balance fertilizer.


Thanks for this, i guess AMS over Urea to decrease soil PH, or for another reason?

Epsom salt make sense for magnesium deficiency.

Are you suggesting i make up my potassium deficiency from a balanced fert? would you not be concerened that the amount of this id require to get potassium up would subsequently raise my phosphate to undesirable levels?


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## lambert (Sep 12, 2018)

What about K Mag?


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## ABC123 (Jul 14, 2017)

liamjones said:


> ABC123 said:
> 
> 
> > I would apply ammonium sulfate fertilizer (21-0-0). AMS is 24% sulfur.
> ...


You can skip the phosphate if you want and just focus on the potassium. Phosphate should be enough to sustain at this level.

AMS would be for the sulfur, it shouldn't impact ph too much but it would over time. But you can always apply it separately if you want to use urea.

Nutrients levels don't need to be perfect, they just need to be not too low or excessive.

https://sturf.lib.msu.edu/article/2012jan24.pdf


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