Two field experiments were carried out at Sakha Agricultural Research Station Farm during 2002 and 2003 summer seasons. Soybean (Glycine max L.) seeds, variety Giza 111 were used to investigate the effect of sulphur, phosphorus and nitrogen levels on soybean productivity and quality. Split-split plot design with three replicates was used. The main plots were assigned by two sulphur treatments [with 120 kg/fed. of elemental sulphur (S1) and without sulphur (S0)]. The sub plots were randomly assigned by two phosphorus treatments [with 15 kg/fed. of superphosphate 15.5% P2O5 (P1) and without phosphorus (P0)]. The sub-sub plots were randomly assigned with four nitrogen levels [zero (N0), 20 (N1), 40 (N2) and 60 (N3) kg N/fed.] as urea fertilizer.
The results can be summarized as: Addition of S1 in the presence of P and N increased seed yield, straw yield, oil%, oil yield, protein % and protein yield and decreased available N, available P, soil pH and 100 seeds weight. Addition of S1 in the absence of P and N led to decrease seed yield, straw yield, weight of 100 seeds, oil yield, protein yield and soil pH and increase oil % in the seeds and soil EC. The P1 treatment increased seed yield, straw yield, 100 seeds weight, oil yield, protein yield, and available P. Also, addition of N levels up to N2 (40kg N/fed )increased seed yield, straw yield, weight of 100 seeds, oil yield, protein yield and available N but it decreased available P in the soil.