Biomass Quality of Brassica Oilseed Crops in Response to Sulfur Fertilization

Abstract

Rapeseed [Brassica napus (L.)], white mustard [Sinapis alba (L.)], and Indian mustard [Brassica juncea (L.) Czern. et Coss] belong to the family Brassicaceae. These crop species synthesize substantial amounts of fat, protein, and glucosinolates (GLS). Brassica species can differ in their concentrations of fat, protein, and GLS in response to S fertilization. Plant material for chemical analyses was harvested from a field experiment conducted in northeastern Poland in 2005 to 2008. The examined species of oilseed crops were fertilized or not fertilized with S applied to soil at optimal rates for each species based on S uptake and forecast seed yield. On average, S fertilization increased seed yield of oilseed crops by 8%, but it did not induce significant differences in the concentrations of fat and protein in seeds. Sulfur fertilization increased total GLS concentrations by 0.22 and 0.27 µmol g−1 dry matter (DM) in the root residues of white mustard and Indian mustard, respectively, and by 0.52 µmol g−1 DM in winter rapeseed. Total GLS concentration in winter rapeseed straw decreased by 0.18 µmol g−1 DM with S application. In white mustard straw, S fertilization increased total GLS concentration by 0.27 µmol g−1 DM. Sulfur fertilization increased total GLS concentrations in the seeds of spring rapeseed, white mustard and Indian mustard by 11.43, 41.75 and 32.05 µmol g−1 DM, respectively. Sulfur fertilization has a significant effect on the seed yield and biomass quality of oilseed crops of the family Brassicaceae.