TheSoilProbe Summer/Fall 2006

Logan Labs Soil Testing and Consulting Services

Vol. 1, Issue 6

Special Interest Articles:

What Can Slow Your Sample 1The McKibben File 2Client Profile 3Logan Labs Calendar 4

Soil Stratification-Problem or Not? By Bill McKibben

A few weeks ago, I ran a wheat tissue analysis for a client of mine who felt thecolor just wasn't quite right. The 4/21 tissueanalysis indicated a number of problems butthe biggest of these which contributed tocolor was a phosphorous deficiency( Table1). The wheat field was resampled in the firstweek of May, only to see the situation getting worse. The first sample apparentlyhad picked up some residual nitrogen in theanalysis from the 28% nitrogen top dressapplication. The weather was extremely dryfor this time of year and by the time the second sampling was complete, the wheat wasstarting into nitrogen deficiency. I must saythat visually color was not to bad at thetime. In the grass crops, I typically see phosphorous, sulfur and zinc go deficient thesame time nitrogen becomes limiting. In thissituation phosphorous and zinc were alreadydeficient but sulfur declined substantially. Bythe time we hit the flag leaf stage some rainhad occurred and the flag leaf tissue data hadsubstantially improved with the exception ofpotassium and zinc. Although the recoverywas very impressive and could have beenmore so with a foliar application pre-joint,damage to the kernel count would havealready been done prior to jointing.Nutrient levels are critical during kerneldevelopment as well as during the fillingperiod. In this case, improving the kernelnumbers during the development periodwith better phosphorous and zinc levels,would mean very little if potassium becomesgoes deficient and impedes the kernel fillingprocess resulting in aborted or light chaffykernels.

The soil analysis indicated over 250 poundsof easily extractable phosphorous. So howcould a soil with that good of level, end upwith a tissue deficiency? Lesson 1: never trusta soil analysis by itself. Tissue analysis is

From the DirectorExpansions at Logan Labs.

The interest in tissue testing is buildingmomentum. Consultants and clients arefinding tissue testing to be an excellent toolto add to their fertility program. To assist ourclients in this area, Logan Labs has pur-chased new instrumentation to expedite thetissue testing process. This new equipmentshould allow us to provide a two day turn-around on plant tissue samples.

Along with the plant tissue analysis instru-mentation, Logan Labs has purchased a “dis-creet analyzer” to be used in the determina-tion of Nitrate Nitrogen and AmmoniumNitrogen in soils. This is quite a uniqueinstrument. It has the capability to run manydifferent analyses. As our clients interestsexpand, we will be prepared to expand withthem.

We are working on putting together a teamof “experts” to provide education and train-ing for you, our clients. We have alreadysecured an expert in soil nutrition, an expertin tissue analysis interpretation, and anexpert in irrigation water issues. If you areinterested in a training session, please con-tact the lab. We look forward to providingyou with the latest information available.

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deficiency in corn and soybeans. In 2005,91% of the corn ear leaf samples that wereanalyzed were deficient in potassium at thattime.

Due to the stratification issue, care must betaken when sampling to prevent the loss ofany part of the core. Loosing part of the surface will give you lower P and K numberson the soil test. As you can see, samplingdepth will certainly effect the kind of numbers that you get on your soil test.Therefore repeat sampling needs to be keptconsistent with the previous sampling ifcomparisons are to be done.

Calcium and magnesium in this study wereremarkably balanced throughout the profile.Soluble forms of these nutrients have beenused on the farm on a regular basis for thepast 5 years.

So how does the solubility data compare tothe standard test data? Tables 2 show themajor element data. Graphically the data forphosphorous is a little different from theinformation gathered on the standard test.The phosphorous level drops off rathersharply through the first three levels butcomes partially back up and levels off. The

Soil Stratification-Problem or Not?continued from page 1

really the only way to verify plant health andthe level of nutrient uptake.

Phosphorous uptake occurs primarilythrough the process of diffusion. Thereforegood root development is essential for adequate phosphorous uptake in the plant.Microbial activity is also important in solubilizing phosphorous therefore temperature and aeration is equally important. In this situation two problemswere occurring at the same time, as is oftenthe case in nature. Initially I perceived theproblem to be one of phosphorous stratification; however, in the process ofchecking for stratification I also found acompaction issue. This farm has not seen aplow for over 25 years. The current tillage isno till and or a combination of Aerwayingand no till. The wheat prior to planting wasAerwayed but over the coarse of the winterand spring, the silty clay loam soils ran backtogether and became very hard especiallywhen the dry conditions set in. Althoughthe compaction by itself was enough toinduce phosphorous deficiency in the wheat;I was curious to find out if there was a stratification problem and if so, how much.After discussing the situation with SusanShaner, owner of Logan Labs, she agreed tofund the research project for an 1.5 inchincremental depth study at two locations onthis field. The field was located in Senecacounty in Ohio on the farm of BobFeatheringill. Bob is an excellent farmer whohas won numerous awards for his efforts insoil and water conservation. The study consisted of sampling the north and southhalves of the field at increments of 1.5 inches. Several cores where taken across theareas and the respective depths were put intoappropriate bags for a composite sample foreach 1.5 inch increment. The sites weresampled to 7.5 inches. A full depth samplewas collected at each sampling site and combined to form a composite sample oneach of the north and south halves.

Part of the data collected is represented ingraphs 1 and 2. Phosphorous and potassiumshowed the most dramatic decline in the soillevels with respect to depth. Approximately68% of the phosphorous in the south and60% in the north was located in the top 3 inches. Consider the ramifications ofplanting row crop seeds 1-2” deep. As much

as 40 % of your phosphorous could be abovethe seed relatively unavailable. Compactionand dry weather could easily seal the fate ofany phosphorous availability. Row cropclients who have been no tilling for quitesome time and using no starter fertilizercould seriously jeopardize plant health especially in stress conditions. Assuming surface phosphorous may be unavailable dueto seeding depths, phosphorous at the deeperdepths may be unavailable due to the coolsoil temperatures. As planting dates getpushed up earlier and earlier, this issue willbe exacerbated. Turf clients might escape the seeding depth issue but dry weather ,compaction along with poor water qualityfor irrigation can be just as devastating tophosphorous availability. Whether you aregrowing row crops or turf, applying lime,gypsum, trace elements such as iron, manganese and zinc will rapidly reduce thesolubility of phosphorous.

Potassium follows the same pattern as phosphorous but not quit as dramatic adecline in the soil profile(Graph 2).Potassium is just like phosphorous in thatuptake is primarily by diffusion and requires agood root system to provide adequate levelsto the plant. Potassium is my number one

standard test continued to fall through alllevels.Phosphorous could pose an environmentalthreat, even in no till situations since thebulk of the phosphorus is in the top 3 inchesand the most soluble phosphorous is in thetop 1.5 inches. Phosphorous pollution is primarily an erosion problem. No till has thelowest level of soil loss; however, when a rainevent does exceed infiltration rates on minimal or no till situations, the level ofphosphorous pollution could be very high.

The potassium acts much the same way asphosphorous except it comes back to almostits original level in 3.0-4.5” and then levelsoff. The magnesium falls off after the firstincrement and levels off.

Calcium solubility data(Graph 5) , unlikecalcium from the standard test which was relatively constant, acts more like phosphorous did in the standard test(Graph1) with most of the available calciumbeing in the top 3”. This seems logical sincemost of the nitrogen applications and rootsare located in this area. The acidifying effectsfrom the nitrogen , organic acids from theroots and organic matter decompositionwould help solubilize calcium. These fields

have had gypsum applications which mayalso contribute to the surface solubility of calcium. When looking at the balance ofnutrients in solution, there seems to be astrong inverse relationship when soluble calcium declines in solution (Graph 6). Theppm of sodium stays fairly constant in theprofile; however, the percentage of sodium insolution increases proportionally withdecrease of calcium. In this instance thesame is also true with the percentage of magnesium.

In an attempt to understand solubility, onemust always keep in mind that based on thecrop and growing conditions, thresholdamounts of nutrients must be kept in solution. At the same time a balancebetween the nutrients in solution should bemaintained. Just having the balance is notgood enough. One must also maintain theoptimum levels of nutrients. The level ofnutrients in solution will certainly be affectedby the amount of nutrients on the colloidand the many biological and physical factorswhich effect the movement of nutrients intosolution. Those optimum levels can be determined by correlating tissue analysiswith the soil solubility tests.

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Barry Dunn has been with Logan Labs as theLab Manager since our beginning. Barry isusually the first person to see your sampleswhen they arrive at the laboratory. Barry isresponsible for all of the preparation andanalysis of the soil samples at Logan Labs.He monitors our quality control program anddaily work flow. Barry is an early riser and isalways the first person to arrive at the labevery day. This plays a big part in the quickturn around time we have been able to pro-vide for you. Barry enjoys hunting and fish-ing, and almost anything else that allowshim to be outside.

Meet Logan Labs Soils Lab Manager

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Requesting Extra TestsSometimes after reviewing a report, a client will discover the need for additional testing. Feel free to contact us for any additional testing needs. We keep all samples in the lab for aminimum of four weeks. If space allows, we will keep them longer.

Don't let this happen to you!

Don't waste valuable time and money by having yoursamples arrive at the lab looking like this. Rememberto pack samples tightly in a box. If the samples canbounce around inside of the box, they will be one bigsample by the time they reach the lab. We don't want to call youwith the bad news that your samples have been compromisedduring shipment. Please take the extra few minutes to pack thesamples safely. It is well worth your time.

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LOGAN LABS, LLC184 W. Main StreetP.O. Box 1455Russells Point, OH 43348

LOGAN LABS, LLC184 W. Main StreetP.O. Box 1455Russells Point, OH 43348

Toll Free: 888-494-SOIL (7645)Phone: (937) 842-6100Fax: (937) 842-2433e-mail: susan@loganlabs.com

Hours: Mon.-Fri. 7am-4pm

web site: www.loganlabs.com

Logan Labs Calendar

Office hours 7 a.m. to 4 p.m.

Holidays – Lab Closed

January 2 New Year’s DayApril 14 Good FridayMay 29 Memorial DayJuly 3 & 4 Independence DaySeptember 4 Labor DayNovember 23 & 24 ThanksgivingDecember 25 & 26 Christmas

Look for Logan Labs at the following shows:

Ohio Turfgrass ConferenceColumbus, OH

December 5-7, 2006

Acres, USA ConferenceSt Paul, MN

December 7-9, 2006

Great Lakes Trade Exposition

Grand Rapids, MI January 8-10, 2007

Golf Industry ShowAnaheim, CA

February 22-24, 2007

Be sure to make a note of our new website address:

www.loganlabs com

<http://www.loganlabs.com/>

Announcing NewWebsite Address

Future NewslettersWe are welcoming specific questions fromour clients for our future newsletters. We willdo our best to provide you with answers. Wewould also love to hear about your successstories. If your question or story is used in anewsletter, you will be credited with $100 insoil testing.

New PricesA new price schedule went into effect onDecember 1, 2005. Please call the lab if youhave not received the new schedule.

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