Using surface roughness engineering of nanomaterials, a research team provided an effective guarantee for improving crop nutrient efficiency and thus reduced environmental pollution by nitrogen fertilizer.

The team, led by Prof. WANG Guozhong and ZHOU Hongjian from the Institute of Solid State Physics (ISSP) of the Hefei Institutes of Physical Science (HFIPS), successfully used micro-nanostructured hollow silica spheres, which looked like sea urchin under scanning electron microscope, as a novel carrier to improve the adhesion capacity of foliar nitrogen fertilizer (FNF).

In this research, three kinds of micro-nanostructured silica spheres (e.g., solid silica spheres (S-Si), hollow silica spheres (H-Si) and sea urchin-like micro-nanostructure hollow silica spheres (SUH-Si)) with similar particle diameters, different surface roughness, and different morphologies were successfully utilized as novel carrier materials to load nitrogen fertilizer and improve the adhesion capacity of the FNF on plant leaves.

Compared with the traditional FNFs, both the adhesion capacity of the FNF based on three kinds of micro-nanostructured silica spheres on the leaf surface of crop, and their nitrogen utilization efficiency on the growth of maize seedlings were significantly improved.

Above all, the utilization rate of FNF with SUH-Si on maize leaf was increased by 2.29 times as the increased loading of NH₄Cl on the particles with higher roughness effectively adhered to the leaf surface and increased the release of nitrogen to the leaf.

"It's because a large number of nano-tubular structures on the surface of SUH-Si, SUH-Si-N were clung between the micro-papillae and irregular grooves of peanut leaves and adhered between the micro-papillaes of maize leaves, resulting in ultra-strong adhesion capacity of the SUH-Si-N on the leaf surface." said Prof. ZHOU.

This research work realized the efficient use of FNF and provided a reference path to improve the adhesion performances of other foliar fertilizers.

Figure 1. Morphology of S-Si, H-Si and SUH-Si. (Image by LI Wenchao) 

Figure 2. Digital photo of maize seedlings before and after 7 days, 21 days of foliar nitrogen fertilizer. (Image by LI Wenchao) 

Figure 3. Plant traits of maize seedlings sprayed with foliar nitrogen fertilizer. (Image by LI Wenchao)