Nitrogen question ????

I got back my soil reports last week but just got back the nitrogen part this week. They (MSU) gave me the nitrogen levels in each field as a % and my question is how do I convert that to how many pounds of nitrogen per acre. I wanted to look at how much nitrogen is there but telling me its 0.09% doesn't help when they say I need 100 lbs of nitrogen per acre for my crops. Does anyone know what formula to use to convert 0.09% Nitrogen per acre to X-pounds of Nitrogen per acre. My soil is sandy loam if that info is also needed, as I would think there may be a difference between sandy soil vs clay but not sure.

I think the assumed weight of an acre of soil is 1000 tons.  I'm not sure if.that helps and I'm not sure what the 0.09% means in relation to your nitrogen (is that how  much is there? The level you want to get it to?). But if you take the 1000 tons (2 million pounds) and you know you want it to be x% nitrogen, the difference between that goal and what is currently there would tell you what you should add

The 0.09% is what MSU said I have but then they say it needs 100 lbs of actual N to the acre for tomatoes and peppers I planned on planting there. So I need to either convert 100 lbs of actual N to % or I'd rather convert the % to lbs as all the recommendations are in ponds per acre and the test shows all other things (ie P-K-Ca-Mg-Cu etc) in pounds per acre.

I was told in my soil tests (1st # for field 1 and 2nd # for field 2) pH=6.6-6.0, P=303-145 pounds per acre, K=283-173 ppa, Ca= 1674-778 ppa, Mg=182-65 ppa, S=288-216 ppa, Zn=11.5-3.1ppa and CEC= 6.1-4.4 and %OM= 2-1.5 but instead of saying how many pounds of nitrogen (they normally don't test for N, but I paid extra to get results but those results said I have 0.09% nitrogen in field 1 and 0.06% nitrogen in field 2... I called my local county extension office and he didn't know how to convert from % N to how many pounds of Nitrogen I actually have in my soil atm. I know that this nitrogen test isn't accurate as here in Mississippi we have high temps, high humidity and high biological activity in the soil that converts organic and inorganic Nitrogen into both plant available and nitrogen gas that then leaches into the air so this test is just to see aprox. how much I have normally as I do almost the same every year by planting clover for winter cover crop and incorporating it into the soil in early spring and adding 5-7 tons of composted chicken manure to each acre along with some ash, biochar and worm compost as available. I only wanted to know pounds of N per acre so when either testing soil at another place that gives me N in ppa I have an apple to apples not apples to fish comparison. I am also trying to see what my additions are doing to my soil as I've been doing this same routine for about 2 years on 1 field and 3 years on the 2nd field. It is correcting the pH as both fields had a pH of 5.5 or lower and all nutrients were on either low to mid and now are on high to very high and even the OM (organic matter) has risen slightly along with the cation ion exchange CEC. The only bad thing (if you want to call it that) is adding this much manure is raising the P faster than N-K and micro's but I knew that manure has a high ratio of "P" vs other nutrients so I just need to lower my tons per acre of that and increase my organic nitrogen and potash (looking at cottonseed meal, feather meal etc for N and either greensand or ash to raise K) without adding any P.

MSU also gave me recommendations for fertilizers BUT they only give it in actual pounds needed per acre AND its for chemical fertilizers so I instead have to do way more figuring AND MATH when using organics as they usually have way lower %'s than chemical fert's but I'm not gonna use chemical fert's if I can avoid it as this land has not seen chemical fert's for over 40 years and was pastures for cattle and sheep most of that time and only had lime put on them when broomsage became an issue in the pastures.

Can you attach a copy of the soil test result.

In the sample one that I have below, you can see that Nitrogen is usually given in ppm similar to trace minerals. Did you do a regular soil test or saturated paste test. I know that each lab uses a slightly different setup. So if we see it it would help us a bit more

s. lowe wrote:I think the assumed weight of an acre of soil is 1000 tons.  I'm not sure if.that helps and I'm not sure what the 0.09% means in relation to your nitrogen (is that how  much is there? The level you want to get it to?). But if you take the 1000 tons (2 million pounds) and you know you want it to be x% nitrogen, the difference between that goal and what is currently there would tell you what you should add

After doing a search I also saw about that number, they said that a furrow slice (6.7" deep) of loam soil is 2,024,458 pounds for 1 acre, but  the more sandy the soil the heavier it would be and my soil is sandy so I'm using about 2.1-2.3 million pounds to get an aprox. estimation.

so.... 2,100,000 lbs x 0.09% N= 1890 lbs of N, but if 2,300,000 x 0.09 then its = 2070 lbs of N per acre so this still isn't what I was looking for as the other place I get soil testing done is from a local additive called Suma-Grow which is an additive I use that is Humic acid base with beneficial microbes and fungi to help the soil. They will test my soil for free after buying the product. I'm not sure if they do this for everyone as they are a local company but sell all over the world and I was using them when they were first starting out and have helped with some local testing they did on their products. But their test (suma-grow's) shows nitrogen in how many pounds per acre BUT not total Nitrogen but actual plant available nitrogen. This 1890-2070 pounds of nitrogen is total which includes organic and inorganic and includes all forms even those not available for the plants to uptake. So I thank ya'll for the help and everyone who helped guide my extensive web search, John n lowe you both helped me to change what and how I searched and guided me, BUT the answer I got was not what I needed so overall I wasted a few bucks having this test from MSU but learned allot and now have more info on my farm, just not the apple to apple comparison I was hoping for. One advantage of my use of the organic manure is it is a slow release and it only releases about 1/3 of its N per year so you also need to add that unused part into it as it then becomes an additive effect (ie my manure has 36 lbs N per ton BUT only 12 lbs is plant available  this year, but next year I then have 12 lbs + 12 lbs, and on year 3 I'd have 12+12+12 as long as I kept adding 1 ton of manure per year. (I actually do 5-7 tons)

S Bengi wrote:Can you attach a copy of the soil test result.

In the sample one that I have below, you can see that Nitrogen is usually given in ppm similar to trace minerals. Did you do a regular soil test or saturated paste test. I know that each lab uses a slightly different setup. So if we see it it would help us a bit more

I'm not at the house atm but will try adding my pdf files MSU sent to my e-mail this weekend (if it rains) if no rain then I'll be spreading 22 tons of manure w/ my 1950 Farmall Super A and a pull type spreader...

s. lowe wrote:I think the assumed weight of an acre of soil is 1000 tons.  I'm not sure if.that helps and I'm not sure what the 0.09% means in relation to your nitrogen (is that how  much is there? The level you want to get it to?). But if you take the 1000 tons (2 million pounds) and you know you want it to be x% nitrogen, the difference between that goal and what is currently there would tell you what you should add

That would give you the weight of the top six inches of soil at right about 10% moisture content.  Hard to even guess really, moisture content makes a massive difference in weight and who knows to what depth you be considering?  

I have never even heard of soil nitrogen being expressed as a percentage before.  Even that would tend to be a gradient dependent upon depth.  I don't think one could even guess until they had a better definition on how the measurement is actually being defined.  Dry soil is estimated at 82 pounds per cubic foot and with 43,560 square feet per acre that would be 3.6 million pounds in 43,560 cubic feet.  Though even that is problematic as acreage is measured by flat ground area not by surface area, some fields out here on the Palouse like my last farm can have 20% to 30% more surface area per acre with the steep hills in the fields than a flat field has.

I am with the OP, he really needs a pounds per acre Nitrogen reading.

Your number of 0.09 is just about 0.1. I am going to assume this is for ammonium and that your nitrate level is about 16. This means that your soil has about 60lbs/acre.
You can see that I am doing alot of assuming (ass-u-me) which can be bad so I will have to wait until you post the document.
So my formula was 0.09 x 160 = 16ish of nitrates then I multiply by 4 get lbs/acres.



Soil Test Laboratory Analyses
Ammonium-N is just as available to plants as nitrate-N, but typically little accumulates in the soil because it is readily converted to nitrate under most conditions. However, if N fertilizer was recently applied, there may well yet be some ammonium N available in the soil for plant use.

Significant levels of soil ammonium are most likely if anhydrous ammonia was the N source, a nitrification inhibitor such as nitrapyrin or dicyandiamide (DCD) was used, and/or soil pH was low (below 5.5 ). In these situations, low levels of soil nitrate may indicate little conversion of ammonium to nitrate, rather than simply loss of nitrate.

If soil test values for ammonium and nitrate are reported as "ppm" or "mg/L" nitrogen (NH4-N or NO3-N), then pounds per acre of available N are calculated by multiplying the test results by 4 when the sample depth was 1 foot. For other sample depths, divide the sample depth (in inches) by 3 and then multiply by the test results.

Example:
Soil NO3-N in a 1-foot sample was reported to be 30 ppm.
Conversion from ppm to pounds per acre is (12 inches / 3) x 30 ppm = 120 pounds per acre.

If soil test values are reported directly as NH4 or NO3, then these values must be converted to an ‘N’ basis first. The calculations are: NH4-N = (NH4 / 1.2) and NO3-N = (NO3 / 4.5).

Example:
Soil NO3 was reported to be 90 ppm.
Conversion from NO3 to NO3-N is (90 ppm NO3 / 4.5) = 20 ppm NO3-N.
https://www.agry.purdue.edu/ext/corn/news/timeless/AssessAvailableN.html

A typical agricultural soil in the Willamette Valley contains about 0.10 to 0.15 percent N, or approximately 5,000 lb N/acre in the surface foot. Only 1 to 4 percent of this total N becomes plant-available during a growing season. East of the Cascades, soils tend to have smaller amounts of total N.
Total N analysis, while not recommended as part of a standard soil testing program, may be better than organic matter analysis for estimating soil N supplying capability. *pg2 https://piercecd.org/DocumentCenter/View/670/OSU-Soil-Test-Interpretation-002?bidId=

So with 0.10 percent N or 5,000 lbs/N in the surface foot and 2% available aka 5,000/50 = 100lbs/acre. But 1% bio-availability would be only 50lbs and 4% available would be 200lbs/acres. Its such a wide range.

S Bengi wrote:Can you attach a copy of the soil test result.

In the sample one that I have below, you can see that Nitrogen is usually given in ppm similar to trace minerals. Did you do a regular soil test or saturated paste test. I know that each lab uses a slightly different setup. So if we see it it would help us a bit more

Here is the pdf file they sent BUT the nitrogen levels were hand written on the hard copy they mailed me so when looking at this just know that the fields marked as "1A" had 0.09% Nitrogen and field 2B had nitrogen as 0.06% (also field 1 has had 2 years of manure added to it vs field 2 which only had manure added 1 year and I'm adding manure to both fields this weekend.

Also note in that report that MSU doesn't list organic ferts, they only show recommendations for chemical ferts. though I only use organic ferts, rock minerals, and manures etc...

Why not call them and ask?  If you can't contact the lab, contact any prof in the age dept.

Your soil needs at least 5 times the amount of organic matter that it currently has, bringing that up will help your nitrogen problem.

I would focus more on adding carbon than on adding nitrogen.

Also based on the 160lbs of nitrogen that they are asking you to add, they are basically saying that your soil has no nitrogen and to just buy, buy, buy nitrogen.

S Bengi wrote:Your soil needs at least 5 times the amount of organic matter that it currently has, bringing that up will help your nitrogen problem.

I would focus more on adding carbon than on adding nitrogen.

Also based on the 160lbs of nitrogen that they are asking you to add, they are basically saying that your soil has no nitrogen and to just buy, buy, buy nitrogen.

This, 100%.  Cover crop it before, during, and after vegetable season.  Also research subordinate crops.  Soil can give you all the nutrients you need.  You just need to give the soil all the workers and converters it needs.  I'd put it to winter rye each fall, and then carefully interseed things like clover, flax, barley, chicory, wildflowers, and anything else you can figure how to manage with mowing and season variation.  Every plant pumps carbon and nutrients into the soil via root exudates.  Harness that, and you'll never need the bag again.  The one fertilizer I still use is gypsum, and that is only for the sulfate.