Quality assessment of commercial biofertilisers and the awareness of smallholder farmers in Gauteng Province, South Africa

Abstract

This study aimed to evaluate commercial biofertiliser quality and awareness amongst smallholder farmers in Gauteng Province, South Africa. Sixty-seven smallholder farmers were interviewed in Gauteng Province by using a survey method, while the physicochemical and microbiological properties of 13 biofertilisers were evaluated using laboratory experiments. The results showed that awareness and use of biofertiliser are very poor, with 96% of the smallholder farmers surveyed not having biofertiliser knowledge. Furthermore, the products lack basic quality parameters: 54% contained no biofertiliser strain while all the products contained microbial contaminants. The pH, moisture content and viable microbial densities were below the acceptable standards for some of the products. Two fungal and 58 bacterial operational taxonomic units were obtained from the 16S rRNA Sanger sequences while 5 791 OTUs were obtained from the Illumina Miseq system. Approximately 40%, 41% and 59% of the isolates were positive for nitrogen-fixation, siderophore production and phosphorous solubilisation. Overall, there is a need to improve awareness amongst farmers and promote good-quality biofertiliser products for increased crop productivity.