# How many g of fertilizer per kg of soil?

freedom21February 22, 2011

I am not sure that is the right place to post but you may help me

I need to calculate how much of Se there is per kg of soil in the 0-30 cm soil layer (bulk density 1.3 g per cm3)if I will apply 10 g of Se per ha.

They told me that the answer is 2.6 um per kg, but I can't find how they calculate it

Thanks

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bluegoat_gw(Zone 3b)

The trick is to know that an acre furrow weighs about 2,000,000 lbs. That is one acre by the depth of a moldboard plough - 6.67" and with soil bulk density of 1.3 gms/cc weighs 2,000,000 lbs.

This gives you a convenient conversion to ppm. For example, adding 2 lbs. per acre of a nutrient is adding 1 ppm. Since soil analysis gives values in ppm or ppm equivalent, it is easy to determine fertilizer application on a per acre basis.

You will need to do some metric conversion but this should be the way to go about it.

A depth of 30 cm. is deeper than 6.67"; it's nearly a foot. There may be a metric version that is a hectare by 30 cm deep. How much does that weigh? Bulk density is 1,300 kg/m^3 metrically.

1 hectare = 10,000 m^2 * 0.3 m = 3,000 m^3

3,000 m^3 * 1,300 kg/m^3 = 3,900,000 kg

How useful is that?

Anyway, that's my contribution. Good night.

February 23, 2011 at 1:24AM
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bluegoat_gw(Zone 3b)

Since no one has finish off this question, I will try with a bit of Grade 7 math.

10 grams = 0.01 kgs.

0.01 kgs. / 3,900,000 kgs. = 2.564^-9 kgs. per hectare

That's seems closer to nanograms than micrograms.

In other words, compost made from diverse materials should provide this level of Se. I have no idea of how else one would add that small a quantity with accuracy.

February 24, 2011 at 6:35PM
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Bluegoat's answer is correct i.e. 2.564 micrograms per kg (but not nanograms. 10^-9 kg is 1 microgram).

February 24, 2011 at 8:38PM
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bluegoat_gw(Zone 3b)

I know that I should not argue with a Saskatchewan farmer but then there is a chance that you are not a farmer. But since you are correct, you probably are a farmer.

Nano-kgs. become micrograms. That's what I missed. Thank you.

February 24, 2011 at 10:08PM
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goren

For the rest of us who talk english might the writer tell us why the use of b.s. malarkey, h.s., and an attempt to prove she got through kindergarten does for the gardener who thinks in pounds, inches, acres and yes, even hectares...
Dealing with fertilizer in specific terms involving grams is hardly something that will catch the eye of the reader.
Since a gram is just about the smallest measure to deal with in most instances of gardening, it would be better for the writer to catch up to the 20th century.

February 25, 2011 at 7:00PM
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goren,

Not sure who you're referring to but I suggest that you may have some adapting to do yourself. I mean, who the heck uses pounds and inches, besides for a few Americans? I sure don't and I never have, all my life. I measure everything in grams, metres and litres, thank you very much. Metric is what scientists use, and metric is the only globally accepted system of measurement. As for your last sentence, look up what kilograms are.

Trust me, life is much simpler in metric.

February 25, 2011 at 7:27PM
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Lloyd

;-)

Lloyd

February 25, 2011 at 7:41PM
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mahmoud_seleiman_helsinki_fi

Could please kindly tell me, what is the role for the approximately number of Kg of soil per hectare? And do you have reference for this that I can use it? because I would like to caculate how many kg Cadmium (Cd) cand be found in one hectare. I know howm any g of Cd is found in Kg soil.Ã¯Â¿Â½

please send me email on mahmoud.seleiman@helsinki.fi
Regards
Seleiman

March 8, 2011 at 3:42AM
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