Our Response to NCSU

Our Response to The Tobacco Specialists at North Carolina State University

 

 by

 

Ray DeBruhl

 

The tobacco specialists at the Crop Science Department of North Carolina State University (NCSU) claim that we are  misinterpreting their literature as printed in the Flue-Cured Tobacco Production Guide. They claim that we are making misleading statements about the literature.

 

Here is the statement we have posted on this website:

The 2014 Flue-Cured Tobacco Guide states that “Research has shown that a wide range of particle sizes is most suitable” for the float system. But they do not explain what that means nor do they tell you which commercial mix has that attribute. This valuable information that will allow you to make better management decisions has not been shared with you by the NCSU tobacco extension specialist.

Although we will make reference here to the material printed in the “”2015 Flue Cured Tobacco Production Handbook, the information that we share here with you has been repeated for over 10 years in the same annual issue of this publication. You may refer to page 50 of the 2015 edition under the heading, “Select a High-Quality Growing Medium”, as we address their claims.

However, before I address their claims, allow me to address why this entire matter is problematic for the NCSU tobacco specialists. NCSU has been publishing the same advice for over 10 years as to what constitutes a good soil mix for growing tobacco plants in the float system. And, it is our opinion that they are correct in stating that a soil mix which has a “wide range of particle size is suitable”, (although they are saying we are misinterpreting what that means). However, the very soil mix that the majority of growers have been using during this 10 plus year period is opposite to the advice they give in the “Flue–Cured Tobacco Production Guide”. Growers have been using a fine texture soil mix with a “narrow range of particle size distribution”. They have not been using a coarse texture soil mix with a”wide range of particle size distribution” as the tobacco specialist recommends in the production guide. The reader should not underestimate the importance of using a soil mix that has a”wide range of particle size distribution”, which is a coarse texture soil mix.

It is very interesting that as the result of our educational program to teach growers the facts about soil media, over 50% of growers switched this growing season (2015) to a soil mix that has a wide range of  particle size distribution, a coarse texture soil mix.

So, one must ask the question, why? Why did they recommend one thing and knowingly allow growers to use something that is opposite to what they recommended? It isn’t because there wasn’t a soil mix available that met this criteria, because there was a soil mix on the market that had “a wide range of particle size distribution”.

NCSU tobacco specialists recommendation was to select a soil mix that has a “wide range of particle size distribution”, which is coarse texture. However, they knowingly allowed the majority of growers to select a soil mix that has a “narrow range of particle size distribution”, which is fine texture. With this in mind, I will address their claims. Keep in mind, that it is our belief that the tobacco specialist does not understand the literature they have printed. This is because the literature they published is not crop science literature but literature borrowed from horticulture research.

The second line in the paragraph on page 50, “Select a High-Quality Growing Medium” states, that the grower should consider, a medium’s particle size distribution and nutrient charge to determine its suitability for transplant production.” The NCSU tobacco specialist is making reference to the fact that particle size distribution is important and should be considered before selecting a soil mix.

According to Shein (2008) definition of particle size distribution – The particle-size distribution is the relative content of elementary soil particles of different sizes (independent of their mineralogical and chemical compositions) in a soil sample.

A tobacco specialist spoke to me in the spring of 2015, about our statement and said, “ the statement in the Flue-Cured Tobacco Production Guide meant that any particle was appropriate, either large, medium or all small.” He stated that I was misinterpreting what particle size distribution is. Does the specialist mean distributed over one particle size?  That’s absurd, “particle size distribution” implies particle size distributed over a range of sizes.

However  scientific literature defines particle size distribution differently than the tobacco specialist that spoke to me does.  As Shein stated, “ it is the relative content of soil particles of different sizes.” The NCSU tobacco production guide stated “particle size distribution”,  it did not state all of any one size particle.

It is interesting that the NCSU specialist should have known that it is not physically possible to have peat moss substrates all of any one particular size. His statement reflects no understanding of the structure of substrate materials.

The next statement in the paragraph,“Select a High-Quality Growing Medium”, on page 50, states, “Particle size in a soilless medium is similar to soil texture and is determined by the relative amounts and the size of the mix’s components”. Again the literature as printed is implying more than one size.

Read above Shein’s definition of particle size distribution. The NCSU tobacco guide is giving the same definition, albeit unknowingly,  that particle size distribution is the relative content of soil particles of different sizes.

In line 6 of the paragraph in question, the “2015 Flue Cured Tobacco Production Guide” reads, “Research has shown that a “wide range of particle sizes”  is suitable. Again the NCSU specialist stated that this meant that any particle was suitable”. If the NCSU specialists were correct, then this should have read a narrow range of particle size distribution is suitable. However it doesn’t state that and the specialists are not correct, they are totally wrong. (for the readers information, a narrow range of particle size distribution would mean that there are relatively few different sizes of soil particles). And yet they knowingly, year after year, allowed growers to use a fine texture soil mix which has a narrow range of particle size distribution, when they were recommending a soil mix with a “wide range of particle size distribution” , which is a coarse texture soil mix.

If the tobacco specialist had informed the growers of the problems that are associated with using a fine texture soil mix, then the growers could have made better management decisions in growing their plants. See the video, “Problems associated with using a Fine Texture Soil Mix”.

A lot of problems could have been avoided over the years if only the growers had been using a soil mix that had a “wide range of particle distribution”, as the production guide recommended. Soil mix that have this characteristic are coarse in texture. There are several problems associated with using a fine texture soil mix which has a “narrow range of particle size distribution” .

The problem with the NCSU tobacco specialists’ claim is that the entire preceding lines of content in this paragraph on page 50 makes constant reference to a wide range of particle size distribution. And as stated above, NCSU’s own printed literature matches Shein’s definition of particle size distribution. So, the North Carolina State University tobacco specialists are wrong, it does not mean any particle is suitable. It means exactly what they printed , that a wide range of particle sizes is preferable to have in a soil mix that is used to grow tobacco plants in the float system. (see the link below for the scientific literature that supports our claims).

This conversation with the NCSU tobacco specialist ended by the specialist making the statement, “ they would settle this once and for all and would do their own testing and settle this.”

Did the specialist mean that they would produce the data to back their claims? That is not scientific research. In fact, there is nothing scientific about that approach. There is an underlying problem with academia today, which is, data can be purchased, (this is playing out in other areas than just soil mix). If their agenda had the grower’s interest first, then just maybe instead of only 10% of growers following their advice to use a soil mix with a “wide range of particle size distribution”, maybe the all the growers would be. Then the problems growers have experienced over the years with soil mix would have been avoided.

In fact, in a thesis written by a graduate student under the tobacco specialist at North Carolina State University, stated, that producers should avoid a soilless medium with high percentages of small particle size. The thesis further stated mixes with high percentage of small particle size are also the ones which accumulate fertilizer salts. Their own research reveals the fact that a fine texture soil mix is not the best for growing tobacco plants in the float system, yet they refuse to tell growers this fact.

A soilless medium with a wide range of particle size distribution would be coarse in texture with a low percentage of small particle size.

One problem growers continue to deal with every year is,”soluble salts”. Proof of this fact is that at every GAP meeting, soluble salts issues are addressed in the agronomic section of the meeting by the NCSU specialist. Fine texture soil mix with its’ narrow range of particle size distribution contributes to soluble salt issues. Again see the video “Problems Associated with Using a Fine Texture Soil Mix”.

As Donald Rumsfield famously said (2003), “Everyone’s entitled to their own opinion, but they’re not entitled to their own facts”

The irony of this issue is that what the North Carolina State University  tobacco specialists published in the “Flue–Cured Tobacco Production Guide” is factually correct, however what they are saying is factually wrong. Further irony is that  they take issue with what we are expressing and claim we are misinterpreting their literature when in fact, what we are stating is straight from horticultural research literature. IN FACT, what they have published is not from their own crop science literature, but it is borrowed straight from horticultural scientific literature.  Maybe they do not understand the horticultural literature they published.

I am reminded by a quote from Sir Arthur Conan Doyle (1892) “It is a capital mistake to theorize before one has data.”

In this case I would modify that quote and say to the NCSU tobacco specialists, “It is a capital mistake to theorize before one understands the data”

One final note, and maybe another irony here. It is interesting that one of the authors of this section, “Producing Healthy Transplants in a Float System” in the Flue-Cured Tobacco Production Guide, is the same NCSU tobacco specialists that stated from 1984 – 1992 that water quality was not important in growing greenhouse tobacco plants. This same author further stated at the time that using battery acid in the greenhouse would harm the tobacco plants.

The reader may find it interesting to know, that Transplant Systems was the only company to introduce and promote good water quality parameters and to advocate the use of battery acid (sulfuric acid) to reduce high levels of bicarbonates in the irrigation water during this time frame, while the NCSU tobacco specialists were telling growers that water quality was not important and that battery acid would harm their plants. ( Click here to read an excerpt on this matter in “History of Transplant Systems” )

They did not understand the significance of water quality then and they do not understand the significance of soil media particle size distribution now.

You may review the educational material that we have prepared to teach the importance of selecting a soil mix with a wide range of particle size distribution and why it is important in the tobacco float system.

Click Here to Access the Material

 &

Click Here to Read the Scientific Literature that Support Our Work

 

(1)E.V. Shein 2008

The Particle-Size Distribution in Soils: Problems of the Methods of Study, Interpretation of the Results, and Classification. The Particle-Size Distribution in Soils: Problems of the Methods of Study, Interpretation of the Results, and Classification.ISSN 1064-2293, Eurasian Soil Science, 2009, Vol. 42, No. 3, pp. 284–291. © Pleiades Publishing, Ltd., 2009. Original Russian Text © E.V. Shein, 2009, published in Pochvovedenie, 2009, No. 3, pp. 309–317.

(2)Sir Arthur Doyle, “A Scandal in Bohemia” in “The Adventures of Sherlock Holmes”. New York: A.L. Burt, 1892