Nitrogen use efficiency of microalgae application in wheat compared to mineral fertilizer

Background Wastewater from sewage treatment plants contains high levels of nutrients, which can be used for plant nutrition. Classical wastewater use complex microbial consortia autotrophic and heterotrophic microorganisms biological treatment. Certain microalgae (e.g., species the genera Chlorella, Scenedesmus, Pediastrum) accumulate nutrients very effectively. Aims We investigated potential biomass obtained a prototype as source crops, focusing on nitrogen. Methods provided wheat with different algae equivalent to 60, 120, 180 kg N per hectare or mineral fertilizer (N, P, K) amounts contained in algal biomass. Physiological phenotypic traits were measured during growth, including vegetation indices, photosynthetic performance, nitrogen efficiency (NUE). In addition, adundances Bacteria, Archaea fungi genes ammonium oxidizing Bacteria determined rhizosphere differently fertilized plants. Results Microalgal application at 120 ha–1 showed significantly improved physiological yield nutrient uptake compared unfertilized control. Nevertheless, their yields NUE lower than equal fertilization, while adundance microbes ammonia-oxidizing not affected. Conclusions Microalgae treatments form suitable organic only moderate reductions fertilizer.