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Tasmania Australia

Hi, I am just interested to find out if anyone knows what the ideal Nitrogen % or ppm is ideal in the soil.
Been doing a fair bit of looking around but yet to come up with an answer.
My soil test says Total Nitrogen is 0.347% I think if i have worked it out correctly, that is 3470 ppm
I am just trying to find out what the ideal Nitrogen range is.
If anyone has any information on this it would be greatly appreciated.
Cheers.
Peter.

2/18/2018 5:20:46 PM

Germany

Well, it depends on the availability of this nitrogen. 3470 ppm is correct, but 3470 ppm of water soluble nitrogen (as ammonium and nitrate) would be sort of deadly for your plants. I guess the 0.347% nitrogen you find in your report refers to the load of nitrogen in your organic matter (let´s assume you´ve got 15% organic matter in your soil, may it consist of 90% of carbon and nitrogen and let it have a C/N ratio of maybe 30, that would give you 0.34% of nitrogen in your soil (but this nitrogen isn´t water soluble, it will be made available as the organic matter breaks down, usually in the course of a couple of years).

2/19/2018 2:23:54 AM

Germany

Just for the info of others who maybe have been wondering, I´ve had a look at bluesilver´s soil test report, and indeed it was the total nitrogen (including the large amount of N which is contained in the organic matter and isn´t water soluble).

2/21/2018 12:22:36 PM

Deer Park, WI

There are two important distinctions here...what's ideal in the soil and what does the pumpkin need?

What's ideal in the soil is a very difficult question to answer. and quite frankly, unless the soil test is performed the day the seedling goes in the ground, the nitrogen value is completely worthless. Nitrogen is just way to volatile.

Its easier (relatively speaking) to posit what ideal nitrogen is for a giant pumpkin plant. My belief is that 150-200lbs/acre (75-100ppm) is in the ballpark.

The NRAES guide for pumpkin production recommends 120lbs/acre. I like 150lbs/acre. The Patons have determined 200lbs/acre is ideal. We have no clue what the exact answer is, just a range.

We have to start from "0" every season, due to nitrogen motility. 5% of organic matter will provide 150lbs/acre, however that may not be available in the first 1/3 of the season if your soil temps havent reached 55 degrees F yet.

Rather than rely on a soil test for nitrogen (and sulfur) mgt, use math to construct a fertility program that aims to provide 150-200lbs/acre over the course of a season.

Hope this helps.

2/28/2018 6:00:53 PM

Deer Park WA

Or just look at your plant and if its pale green, spindley and not growing very fast add a little....

Our OM is upwards of 13% in a clay based soil so we know there will be lots of nitrogen available as it warms up and breaks down. Reading the plant is about the best method out there for judging nitrogen needs (IMHO).

2/28/2018 7:48:54 PM

Paradise Mountain, New York

Joze - So would that be about three and a half (3.5) to four (4) pounds of nitrogen per 1,000 square feet?

2/28/2018 10:12:28 PM

Tasmania Australia

Thanks heaps for the replies,
Sorry, i completely forgot to respond on here after talking to Pumpking,
Yes, makes perfect sense, and my Om is 8.4% in clay based soil,
So should have plenty when the soil warms up, just add a little at the planting stage as you have mentioned.

3/1/2018 1:31:53 AM

Deer Park, WI

Yes, PB. your math is correct.

3/1/2018 8:30:12 AM