Effect of chemical fertilizers and growth promoting rhizobacteria application on seed yield and yield components of camelina (Camelina sativa L.) under environmental conditions of Ahvaz, Iran

Oilseeds have high nutritional value and importance among agricultural crops for providing calories and energy needed by humans, and are the second food source in the world after grains. Since more than 95% of the vegetable oil consumed in Iran is supplied by imports, research in various agronomic practices, especially applied research on rate and application methods of fertilizers in oilseed crops is necssary. Camelina (Camelina sativa L.) is an annual plant and belongs to the Brassicaceae family. Biofertilizers are considered as new achievements in organic farming. Today, the use of biofertilizers with the aim of increasing soil fertility and producing products in sustainable agriculture is considered as an alternative to chemical fertilizers. Considering limited studies that have been done on Camelina (Camelina sativa L.) in Iran, the purpose of this research is to investigate the effect of combining nitrogen, phosphorus, potassium, sulfur and biofertilizers on the seed yield and yield components of this oilseed crop.

This experiment was conducted with the aim of investigating the effects of growth-promoting bacteria and chemical fertilizers on the yield of camelina. The experimental design was factorial arrangements in randomized complete block design with 18 treatments and three replications in 2021-2022 at Research Farm of Shahid Chamran University of Ahvaz, Iran. Experimental treatments included; nitrogen fertilizer levels based on chemical fertilizer (N0-P0-K0-S0) (C1) and (N50-P50-K40-S100)(C2) and (N100-P100- K80- S200)(C3) and biological fertilizer levels or growth promoting bacteria at six levels included: no inoculation/ control (B1), Nitroxine (B2), Phosphate (Barvar2) (B3), Thiobacillus (B4), Nitroxine+Phosphate (Barvar2) (B5) and Nitroxin + Phosphate (Barvar2) + Thiobacillus (B6). Camelina cv. Soheil was used in this experiment. Urea fertilizer was used as nitrogen, potassium sulfate as potassium, triple superphosphate as phosphorus, and bentonite sulfur as sulfur source. Camelina seeds were inoculated with biological fertlizers.

Results showed that the highest seed yield (2120 kg.ha-1) and biological yield (5803 kg.ha-1) obtained in Nitroxin + Phosphate (barvar2) treatment. In all three levels of chemical fertilizers, biological fertilizers increased seed oil content. The highest seed oil content (45.1%) was obtained in the control treatment without chemical fertilizers and application of Nitroxin. Compared to the control (no inoculation), biological fertilizers had less effect on camelina plant traits, but in combination with chemical fertilizers, they improved the growth and seed yield of camelina.  

According to the results of this experiment, the best fertilizer treatment to increase the seed yield of camelina was the combined treatment of Nitroxin fertilizer + Phosphate (Barvar2) in all three levels of chemical fertilizers.