Enhancing phosphorous availability to canola (Brassica napus L.) using P solubilizing and sulfur oxidizing bacteria

Enhancing the availability of soil nutrients to crop plants such as canola (Brassica napus L.) for oil and grain production is of great significance. Data related to the combined effects of rock phosphate, P solubilizing bacteria, sulfur and sulfur oxidizing bacteria on canola growth is scanty. The present research was conducted in the Research Field of Agricultural Research Center of Safi-Abad, Dezful, Iran. The experimental design was a completely randomized design with eight treatments in three replicates. Treatments including: (1) control, (2) triple super phosphate (80 kg/ha), (3) rock phosphate (160 kg/ha), (4) rock phosphate + organic matter (tea waste, 1000 kg/ha), (5) rock phosphate + organic matter + P solubilizing bacteria, (6) rock phosphate + elemental sulfur (1000 kg/ha) + Thiobacillus sp., (7) rock phosphate + Thiobacillus sp. + organic matter, (8) rock phosphate + elemental sulfur + Thiobacillus sp.+ organic matter were tested in plots measuring 3 x 7 m. At harvest crop yield and the related components were determined. Treatment 2 resulted in the highest amount of yield and stover with a 60 and 92% increase, relative to the control treatment, respectively. The next highest corresponding values were related to treatment 8 at 38 and 70%, respectively, not significantly different from treatment 2. Treatment 8 produced the highest oil percentage, followed by treatment 2 (39% increase) relative to the control. Sulfur treatments resulted in the highest oil percentage. The combination of chemical and biological methods (biofertilizers) can be a favorable method to increase the efficiency of naturally (rock phosphate) and synthetically (elemental sulfur) produced resources and hence optimization of chemical fertilization for crop production.