Biological and Chemical Phosphorus Fertilizers Effect on Yield and P Accumulation in Rapeseed (Brassica napus L.)

English. A field experiment was conducted to investigate different phosphorus fertilizer sources and their importance in rapeseed farms on 2007 at Arak, Iran. Ammonium phosphate fertilizer with 50% P2O5 (APF) was used as a chemical phosphorus source with 3 rates of application, whereas phosphorus solubilizing bacteria (PSB) was a biological source of phosphorus used in 4 rates. Experiment was a factorial arrangement in complete randomized block design with 3 replications. APF levels were: control (AP0), 125 kg/ha APF (AP1) and 250 kg/ha (AP2) application and PSB levels were: control (PSB0), PSB at sowing time only (PSB1), PSB as top dress fertilizer after over wintering only (PSB2) and PSB at dual fertilizing in sowing time and also after over wintering (PSB3). The statistical analyses showed that the PSB3 treatment was the best treatment for the seed yield increase. The highest rate of seed yield (9.9 t/ha) was recorded in dual fertilizing applied both, in sowing time and after over wintering stage of rosette. The interaction effects of phosphorus solubilizing bacteria and ammonium phosphate fertilizer application had not significant effect on plant height, biomass yield, number of silique per plant, seed oil percent and seed yield. Interaction effects of phosphorus solubilizing bacteria and ammonium phosphate fertilizer application were significant for phosphorus content in plant tissues.

English. ammonium phosphate fertilizer, phosphorus solublizing bacteria, rapeseed, yield

15

210-214

2