EFFECT OF SULFUR APPLICATION ON YIELD AND QUALITY OF CANOLA DOUBLE LOW OILSEED RAPE (BRASSICA NAPUS CV. OSCAR)

Sulfur (S) and nitrogen (N) applicaton to canola (double low oilseed rape) was conducted on S deficient soil in New South Wales, Australia. The results indicated that sulfur supply increased seed yield and oil content significantly, certain amount of N (eg. N80) with low (S10) or without S (S0) might increase seed S concentration but high rate N with high S could depress it. Generally, S concentration in vegetative parts were decreased with plant development. There was a peak of S uptake appearing at stem elongation with S supply (Y-0. 0156X2+0. 0012X+0.5276, R2=0. 804) but exponential decrease (Y=3. 7205X-0.595, (R2=0.935) without S. The S concentration in vegetative parts remained relatively stable during flowering and pod filling stages. There was no significant effect of N supply on vegetative S concentration during earlier growth stages (eg. rosette and stem elongation) but the concentration at middle and late stages (eg. flowering and pod filling) was significantly decreased by N application. Total glucosinolates were decreased by high rate N (N160) but increased by S because of a close correlation between seed S and glucosinolate concentration (Y=1.1572e3.5289x, R2=0.8273). However, even at highest rate of S, the glucosinolate concentration was still far below the standard (40u mol/g in whole seed) so that the oil free meal would not affect feeding quality of animals.