Impact of Nitrogen and Sulfur Applications on Seed Yield, Protein, Oil Content, and Fatty Acid Composition of Canola (Brassica napus L.)

Abstract

This study was conducted using a randomized complete block design with eight treatments and three replications in 2017−2019 to investigate the effects of nitrogen (N) and sulfur (S) on the seed yield, protein content, oil content, and fatty acid composition of canola (Brassica napus L.). The experiment involved two levels of N application, N1 (180 kg N ha −1 from urea source) and N2 (240 kg N ha −1 from urea source), and four levels of S application, including S0 (control, without S application), S1 (200 kg ha −1 S powder inoculated with Thiobacillus sp. as 2% w/w), S2 (100 kg S ha −1 from ammonium sulfate), and S3 (100 kg S ha −1 from gypsum). The experiment was carried out in three replications to ensure the statistical robustness of the results. The results revealed some exciting findings, as N application had a significant effect on seed yield, plant N, and seed N. The highest seed yield (4139 kg ha −1 ) was obtained with the application of 240 kg N ha −1 . However, an inverse relationship was observed between the amount of oil in canola and increasing nitrogen levels, indicating a decreasing trend. The sulfur treatments also had a significant effect on seed yield, oil content, protein content, and leaf nitrogen. The highest values of these parameters were obtained from S1 treatment. Therefore, what's the best combination of N and S for growing canola? The researchers recommend using the N2S1 treatment combination in regions with soil and climate conditions similar to that of Shahrekord. The study highlights the importance of simultaneous fertilization of N and S for optimizing canola fertility, and the findings suggest applying 240 kg N/ha and 200 kg S/ ha powder inoculated with Thiobacillus sp. bacteria for the best results. These results highlight the importance of considering both N and S fertilization in canola fertility programs to achieve the best possible yield and quality.