Bioformulations based on plant growth promoting rhizobacteria for sustainable agriculture: Biofertilizer or Biostimulant?

Integrated production in sustainable agriculture aims to improve the efficiency of biological inputs through plant-based bioformulations or microorganisms, which are an excellent source of natural fertilisers. A variety of plant stimulants are increasingly used in crop production for environmentally sustainable agriculture. These products have different names and the designations are confusing. The aim of this work is to clarify what is meant by biofertilizer and biostimulant. A biofertilizer is a bacterial or fungal inoculant applied to plants with the aim of increasing the availability of nutrients and their use by plants, regardless of the nutrient content of the inoculant itself. A plant biostimulant is substance or microorganism applied to plants for the purpose of improving the nutritional efficiency, abiotic stress tolerance and/or quality characteristics of crops, regardless of its nutrient content. By extension, plant biostimulants also refer to commercial products containing mixtures of these substances and/or microorganisms. Plant Growth Promoting Rhizobacteria (PGPR) can be called biofertilisers or biostimulants; PGPR formulations are biostimulants. It can be noted that biofertilisers are included in biostimulants. Key words: Biostimulant, biofertilizer, Plant Growth Promoting Rhizobacteria (PGPR), bioformulation, sustainable agriculture.