A novel FePO4 nanosized fertilizer is as effective as triple superphosphate in sustaining the growth of cucumber plants

The behaviour of nanofertilizers (NF) in plant-soil systems can differ from that of conventional chemical fertilizers due to their peculiar chemical-physical properties. Their effectiveness is still poorly understood. Here, in a plant-soil microcosm, we evaluated the P fertilization potential of a novel nanosized FePO4 NF. We tested the efficacy of a FePO4 NF in sustaining the growth of cucumber plants in a pot experiment, compared to a conventional triple superphosphate (TSP) fertilizer. Plants were grown for 28 days on a P deficient soil and determinations were made of growth parameters, nutrient concentrations in plant tissues, P availability in soil, activity of enzymes involved in C, N, P and S mineralization and the structure of the soil microbial communities. Results showed no significant differences in dry weight, leaf area, SPAD index or root growth between NF and TSP fertilized plants. Conversely, P availability in soil and P content in plant tissues at the end of the experiment were significantly higher after TSP compared to NF fertilization, whereas no major differences were observed for other nutrients. Among the measured soil enzyme activities, similar values for acid phosphatase, β-glucosidase and arylsulfatase activities were found between NF- and TSP-treated soils, the alkaline phosphatase activity presented higher values in TSP- than in NF-fertilized soil, while the protease activity showed higher values in NF- than in TSP-fertilized soils. Microbial community structure of NF- and TSP-fertilized soils showed significant differences for archaeal, bacterial, and fungal communities, although the microbial community profiles generally clustered closer to each other in all treatments. We concluded that the FePO4 NF tested can be an efficient alternative to conventional TSP fertilizers.