On the constancy of the ratio of nitrogen to sulphur in the protein of subterranean clover tops

Abstract
While total N: total S ratios varied widely from 4 to 331 depending on plant part, age, N supply and S supply, there was no discernable trend in protein N: protein S ratios attributable to any of these factors. The results also show that it is difficult to extract all of the non‐protein N and non‐protein S from plant tissue. This could explain the variation in protein N: protein S ratios found by some workers.