Blog > April 2020 > Sulfur Recommendations

Sulfur Recommendations

April 30, 2020

4.30.20 | Sulfur Recommendations from Central Valley Ag on Vimeo.

Last time on Agronomy Focus, we talked about nitrogen fertilizer and creating a fertility program and recommendation for nitrogen to maximize both yield and efficiency. Today we want to discuss Sulfur. We want to reference the same nutrient uptake graphs from the University of Illinois that we referenced last time when we talked about nitrogen. If we look at the uptake curve for Sulfur, we can see it is not quite as steep as nitrogen, but it does turn up steeply around V8 and starts to flatten a little around tassel while staying a little steeper during grain fill compared to nitrogen. We really like to see a little sulfur going with nitrogen in each application. In the video that goes with this article, we talk about a few products specifically. The three products we talk about are:

1)  90% Elemental Sulfur. Elemental sulfur is a good product to provide season-long sulfur through the growing season. It does need to breakdown through a biological process into sulfate to be available to the crop. It’s a great tool for a long term fertility program of every year application to build S levels over time. Usually, it should be fall-applied if you are counting on it for the next season.

2)  Calcium Product SO4. SO4 is pelletized gypsum. It's calcium sulfate. It's already in the sulfate, so it does not need to convert. It is much less soluble than ammonium sulfate, so it splits the difference between elemental sulfur and ammonium sulfate. It works as a fall-applied, spring applied, or an early (before V6) top-dress.

3)  Ammonium Sulfate. AMS is an excellent topdress product. It also works well for spring pre-plant. It is very soluble and already in the sulfate, so it will be available for plant uptake as soon as it gets into moisture. It provides 21% nitrogen as well as 24% sulfur. A 50 – 100 lb topdress can be a great compliment to a urea topdress.  

When we talk about sulfur recommendations, we can base them off the soil test, or we can make a S recommendation based on the nitrogen application. In heavier soils, that recommendation is often about 10% of the total N application. In sandier soils, that recommendation often moves to 15% of the N rec. This is because S can be lost through leaching more in sandy soils, and generally, organic matter levels are lower, meaning we cannot count on mother nature as much for our sulfur needs.  

As usual, the best way to add sulfur to your system is to sit down with one of our FSAs and build a fertility program considering all aspects of your soils, yield goals, application methods, and future plans.   

Corn Nutrient Uptake and Partitioning
Source: University of Illinois

Posted: 4/30/2020 3:37:37 PM by Kelli Reznicek | with 0 comments

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