Polymer-coated rock mineral fertilizer has potential to substitute soluble fertilizer for increasing growth, nutrient uptake, and yield of wheat

More than half of the fertilizer applied to farmers' field is lost, causing significant economic losses. To overcome this, a polymer-coated rock mineral fertilizer was investigated using wheat (Triticum aestivum L. cv. Wyalkatchem). In addition, a multispecies microbial inoculant was added to seeds as a biostimulant to enhance fertilizer use efficiency. Thus, this glasshouse experiment investigated the effect of polymer-coated rock mineral fertilizer with or without a multispecies microbial inoculant on wheat growth in a sandy soil. We hypothesized that the polymer-coated rock mineral fertilizer combined with a microbial inoculant would be more effective than non-coated fertilizer at increasing growth, nutrient uptake, and yield of wheat in sandy soil. Both the polymer-coated and non-coated rock mineral fertilizer, either with or without microbial seed inoculation, increased shoot growth at tillering and maturity but root growth only increased at maturity. Grain yield did not differ between the fertilizer treatments except that they were lower for the non-coated rock mineral fertilizer when combined with microbial inoculation. In the absence of microbial inoculation, soil amended with polymer-coated fertilizer had lower residual soil P and K. The hypothesis that microbial inoculation would improve the growth, nutrient uptake, and yield of wheat was not supported in this experiment. Sequencing of 16S rRNA identified Proteobacteria and Actinobacteria as the key phyla in rhizosphere soil. Fertilizer treatments altered alpha diversity (OTU richness, Inverse Simpson and Fisher indices) but had no effect on evenness. This polymer-coated rock mineral fertilizer has potential to substitute for or complement more soluble fertilizers, but there was no benefit of inclusion of the multispecies microbial inoculant on plant growth or yield.