Evaluating the role of bio-inoculations and organic fertilization in the vegetative characteristics of rapeseed (Brassica napus L.).

Abstract

A field experiment was conducted in one of the fields of Al-Amin area in Dhi Qar Governorate/Al
Rifai District during the winter season of 2023-2024, to evaluate the effect of bacterial inoculation 
(Pseudomonas fluorescens), fungal inoculation (Trichoderma harzianum), and organic fertilization 
(wheat straw compost) on the growth and yield of rapeseed Brassica napus L. cultivar Bactol. The 
experiment was conducted as a simple one-way experiment within a randomized complete block 
design (RCBD) with three replicates, each containing 12 randomly distributed treatments. The 
bacterial inoculum, P. fluorescens, was added at two levels (0 and 12 mL/hole), designated B0 and 
B1 respectively. Similarly, the fungal inoculum, T. harzianum*, was added at two levels (0 and 5 
g/hole), designated F0 and F1 respectively. Their phosphate solubility in solid and liquid media was 
tested. Wheat straw compost was applied at three levels (0, 15, and 30 µg/h), designated O0, O1, and 
O2 respectively. The results showed that the treatment with the addition of 5 g of T. harzianum* was 
effective. The F1 variety achieved the highest average plant height (305.16 cm) and the dual 
treatment of fungus and 30 µg of organic fertilizer (F1O2) achieved the highest averages for leaf area 
(507.83 cm²) and stem diameter (2.98 cm). The triple treatment of bacterial and fungal inoculant and 
15 µg of organic fertilizer (B1F1O1) showed the highest rates for chlorophyll (48.47 SPAD), number 
of secondary branches (87.44), and dry weight (215.77 g).