LSU Soil sample results

Here’s my soil sample results for blueberries, plum/pluots, & peaches. The samples for the peach area & plum/pluot area are natural and completely untreated with anything. And the soil sample from the raised bed for the blueberries was given some soil sulfur , aluminum sulfate & several bags of compost/manure.
With me being completely new to all of this and have never done a soil text before I’m looking for everyone’s opinion on the results!

You can’t go wrong with optimum and high. I’d say you did an excellent job getting your soil ready.

Is that Mississippi river bottomland? Because the unaltered results look outstanding for southern soil.

Yes , I’m about 5 miles from the Mississippi River, and directly on Bayou Lafourche which was a natural diversion of the Mississippi up until the 40’s (I think) when it was dammed off and a pumping station was installed to control the flow down to the Gulf of Mexico . I’m 15 feet above sea level . Lafourche is French for " The Fork".

I really like how LSU makes fertilizer suggestions for each crop on their report. That is a big help. I see two reports for plum but none for peach. Is one of the reports actually for peach trees?

Do you know if they adjust their nitrogen recommendation based on the age of the tree?

I noticed the 2 plum reports myself, but if you look in the upper right hand corner you’ll see that one is marked peaches. Under nitrogen source they show the adjustments per age of tree.

Yeah except ammonium nitrate should not be used for blueberries! Yikes! That would probably kill them all very quickly.

I’m not sure about that! NC State used to suggest it and it was used on many large commercial plantings. I used it every year on my 1000 plants for many years. It worked great, but requires care.

Its difficult to buy it now and my farm supply store does not sell it. They sell a sulfur coated urea with 34% ntrogen

Here’s the full report that came in the mail yesterday.

It is often suggested not to use nitrate because of the limited nitrate receptors blueberries have. But maybe that form is different? Such as this statement here

Which states

“Check carefully when selecting fertilizers: the nitrogen must not be from nitrate, which can be deadly to blueberries (don’t find out the hard way!).”

Also Clemson warns against nitrate (at 595)

Warnings from Purdue university

Warnings from the Missouri council on blueberries

More warnings

The pages did not load in correct order, the second page is actually the last page.

I’ll just steer clear of the nitrate to be safe!!


I agree that Ammonium Nitrate may not be the best choice for the back yard orchard. It is still used by commercial growers in my state of NC, which is a big producer of Blueberries. It must be used be used cafefully, because the N is very soluble and it contains a lot of salt. Since Ammonium Nitrate became a well known component in bomb making, its not as common as it used to be. A very small amount of Ammonium Nitrate goes a long way!

Below is the link from NC State which shows the rates.

I used it for many years on several acres and never had any problems and still use small amounts from time to time. I only use about 1/2 Tbsp per bush before a rain. The advantage from my perspective is that I can carry light weight 1 gallon bucket only about 1/2 full through the field. Ammonium Sulfate works too, but has a tendency to reduce PH which is already very low.

The rates in table one seem high to me. But I’ve seen that often and maybe I’m miscalculating in my head. Sometimes for trees it’s cups per tree per application. The only time I get out a cup measure per tree is on a big pecan.


I agree. My experience is that the state university often suggest too much fertilizer. I normally use about 1/2 of the suggested rate. and add small amounts of N later if required.