Biopriming and mineral fertilizers effects on agronomical performance of rapeseed (Brassica napus L.)

Abstract

Increasing and extending the role of biofertilizers can reduce the need for chemical fertilizers and decrease adverse environmental effects. They can play a significant role in fixing atmospheric nitrogen and production of plant growth promoting substances. Therefore, in the development and implementation of sustainable agriculture techniques, biofertilization has great importance in alleviating environmental pollution and deterioration of nature. In order to study the effects of mineral nitrogen fertilization and biofertilizer inoculation on grain yield and its components of rapeseed (Brassica napus L.) under different levels of sulfur fertilizer, a field experiment in Factorial scheme based on Randomized Complete Block design was conducted in three replications. Experimental factors were as follows: (i) Four levels of chemical nitrogen fertilizer (0, 100, 150 and 200 kg N ha^–1), (ii) Two levels of biofertilizer (with and without inoculation) containing Azotobacter sp. and Azospirillum sp. and (iii) Two levels of sulfur application (0 and 50 kg S ha^–1). Rapeseed yield and yield components had a strong association with the N fertilization, biofertilizer inoculation and S application. Higher rates of N fertilization, biofertilizer inoculation and S application increased plant height, pods number plant^–1, grains number pod^–1, 1000-grains weight, grain yield and biological yield. It seems that moderate N rate (about 150 kg N ha^–1) and S application (about 50 kg S ha^–1) can be beneficial to improve growth, development and total yield of inoculated rapeseed plants. So, it is suggested to use a combination of organic and inorganic fertilizer to achieve the highest yield without a negative effect on grain quality that will lead to sustainable environment.