Pulling from my new favorite book, Mineral Nutrition and Plant Disease, Edited by Lawrence E. Datnoff, Wade H. Elmer, and Don Huber. I have pulled out selected text from the book. It's not word for word, but I have tried to keep the original intent intact. I have include my notes in italics to set it apart from the text of the book. I hope you learn as much new information about sulfur as I did.

Chapter 8 Sulfur and Plant Disease

Justus Von Liebig, one of the founders of modern chemical agriculture understood that the nutritional status of plants was a key factor in a plants susceptibility to disease.

Sulfur-Induced Resistance:

SIR is the reinforcement of the natural resistance of plants against fungal pathogens through triggering the stimulation of metabolic processes involving sulfur by targeted sulfate-base and soil applied fertilizer strategies.

(My Note: That was along sentence, what does it mean? Applying sulfur fertilizers reduces the incidence of disease by strengthening the plants natural immune system.)

In trials, as the S supply was increased reductions of the following diseases are noted:

Sclerotinia (White Mold) and Pyrenopesiza (Light Leaf Spot) in Canola

Bibolaris myadis (Southern Leaf Blight) in corn

Rhizoctonia (Root Rot) in wheat and potato

Rust and Powdery mildew in cereal grains

(My Note: For the hows, whys and citations, you'll need to buy the book)

In addition to reduction of diseases, sulfur acts as an acaricide and controls mite populations. 

Sulfur is a key factor in spore dormancy (My Note: Meaning that fungal spores don't sprout when sulfur is high, see plants pass gas below)

SIR runs parallel with other plant defense mechanisms. (My note: the more defense mechanism you have working properly the better the plant defense is. Think of how on a football team all the defensive players have to do their job at the right time in coordination with the other 11 players, one little trip up and the other team scores.)

A sulfur deficiency reduces SIR 

Proteins and Compounds:

90% of the total S in plants is Cysteine and methionine. Cysteine and methionine are components of 99% of proteins. Reduction in S limits the production of protein in the plant. Amino acid type and concentration in plants are related to the susceptibility of plants to pathogens.

Sulfur is a key component of Glutathione (a non-protein compound), which reduces biotic and abiotic stresses, and increases cell wall strength.

Plants Pass Gas (My Title):

When adequate sulfur is present in the soil, corn and soybeans can release dimethylsufide (DMS), as a pathogen defense when attacked. Emissions in a pathogen infected area are 10 to 5,000 times higher than in uninfected parts of the plant. DMS is highly related to the S nutritional status of the plant, low sulfur in the plant, no DMS. (My Note: plants can conduct their own chemical warfare when given the right tools!) This SIR method needs more research and current findings show that it works more as a growth inhibitor than a rescue response.

Final Comments

The required S rate for SIR may be higher than that which is needed for physiological development.

(My Notes: So this begs the questions;

• Is applying 15 lbs of sulfur every other year enough? 
• Are you currently conducting tissue samples to see that sulfur levels are adequate? 
• Is the current tissue normal level (0.2%-0.4%) enough to initiate the SIR? 

While academia is still trying to figure this out, make sure you are getting some sulfur, every year, every crop, every acre with at least 100#'s of SuperCal SO4.)

Still need the opportunity to prove SuperCal SO4 works?

We have teamed up with the Iowa Soybean Associations on Farm Network to place replicated trials across Iowa. Give them or us a call to find out how to participate.

 Yield Starts Here is a blog for farmers, focusing on increasing yield and profitability by focusing on the soil. It is managed by Craig Dick, a Blogronomist and Sales and Marketing Manager at Calcium Products. Find other articles by Craig and guest writers at http://blog.calciumproducts.com/ .