Metal citrate nanoparticles: a robust water-soluble plant micronutrient source

A series of iron (Fe) and zinc (Zn) plant nanonutrients in citrate form were prepared by an eco-friendly solid-state grinding of the respective nitrates and citric acid. Ball-milling of the as-prepared Fe and Zn citrates resulted in nanosize particles. The as-prepared and ball-milled Fe and Zn citrates were characterized using Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis and differential thermal analysis (TGA/DTA), and powder X-ray diffraction (XRD). The particle size and morphology of the obtained samples were studied using a scanning electron microscope (SEM) and transmission electron microscope (TEM). The obtained nanosized Fe and Zn citrates were analyzed for their plant uptake in the test crop soybean (var. JS-335) using the white-sand technique. The concentration of nutrients was estimated by atomic absorption spectrometry (AAS). A significant increase in nutrient absorption was observed in 6 h ball-milled samples of both Fe (789.8 mu g per g of dry weight) and Zn (443.8 mu g per g of dry weight) citrates. Such an increased nutrient absorption is due to the high mobility of nanocitrates. Therefore, nanocitrates can serve as an excellent source of plant nutrients in agriculture.

Automated summary

Iron and zinc plant nanonutrients in citrate form were prepared by an eco-friendly solid-state grinding method, resulting in nanosize particles after ball-milling. The nanosized Fe and Zn citrates showed significantly increased plant uptake in soybean crops, attributed to their high mobility as nanocitrates. This suggests that nanocitrates can be an excellent source of plant nutrients in agriculture.