The need for sulfur for many crops is approximately 1/12 of their need for nitrogen — research

Most of the nitrogen and sulfur in agricultural crops (except for brassicas such as rapeseed, cabbage, etc.) is contained in proteins. And, as with most animal proteins, the nitrogen to sulfur (N:S) ratio in plants is quite stable and is approximately 12:1, writes pda.org.uk. It is noted that this close interdependence between nitrogen and sulfur can be illustrated by an example from a dataset collected by French researchers, which analyzed agricultural crops for patterns in nitrogen and sulfur absorption. The figures of sulfur accumulation (as SO3) over the season are shown in red lines on two diagrams for wheat and potatoes. The two blue lines indicate the SO3 content calculated based on the measured N content, assuming an N:S ratio of 12:1. "This means that for every 12 kg of N in the crop, there is 1 kg of S or 2.5 kg of SO3. The fact that the blue and red lines match well confirms the principle that the need of these crops for sulfur is closely related to their need for ...