15th-16th March, 2017: 18th Japan Mossbauer Spectroscopy Forum Symposium, Tokyo, Japan

[Z. Klencsar]

The 18th Japan Mossbauer Spectroscopy Forum Symposium was held during the days of 15-16 March, 2017, at the Tokyo University of Science, Tokyo, Japan. At the conference Zoltán Homonnay presented a lecture on the structural characterization and fertilization efficiency of different nanoparticle systems considered as potential soil fertilizers.

Mossbauer study of iron containing nanoparticles as potential soil fertilizers

Z. Homonnay 1, Gy. Tolnai 2, F. Fodor 3, A. Solti 3, K. Kovács 1, E. Kuzmann 1, A. Ábrahám 1,2,
E.Gy. Szabó 2, P. Németh 2, L. Szabó 2, A. Lengyel 1, R. Szalay 1, Z. Klencsár 4

1 Institute of Chemistry, Eötvös Loránd University, 1117 Pázmány P. s. 1/A, Budapest, Hungary
2 Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, HAS, Magyar tudósok körútja 2, Budapest, Hungary
3 Institute of Biology, Eötvös Loránd University, 1117 Pázmány P. s. 1/C, Budapest, Hungary
4 Centre for Energy Research, Hungarian Academy of Sciences, 29-33 Konkoly Thege Miklós street, 1121 Budapest, Hungary

Iron is an important micronutrient for plants. In order to maintain high yield, shortage of iron should be avoided, and soils with low iron content or low iron availability (e.g., due to high pH) are necessary to be treated with appropriate fertilizers. Iron supplement may be provided in the form of water soluble iron compounds, however, in this case, migration of iron and therefore dilution is fast that reduces the efficiency of fertilization. If iron precipitates, or added to the soil in the form of bulk solid particles, slow dissolution can hamper the iron uptake for the plant. Iron compounds in the form of nanoparticles may be helpful because if the size of the particle is suitable, it may be taken up by the plant directly. If the uptake by this mechanism is for any reason not possible, the thermodynamically less stable nanoparticles dissolve slowly and therefore provide a steady source (beacause their migration in the soil is slow) of dissolved iron for the plant root. In our study, we have prepared iron nanoparticles in several forms including magnetite (magnetite-maghemite mixture), hematite/ferrihydrite and even metallic Fe-Co alloy. These nanoparticles were characterized by Mössbauer spectroscopy and some other methods. Uptake mechanism and correlation between nanoparticle properties and uptake efficiency is searched for. First results on fertilization efficiency for some nanoparticles will also be reported.

Acknowledgement
Financial support from the National Research, Development and Innovation Office - NKFIH (K 115913 and K 115784) is gratefully acknowledged. The authors are thankful to Fruzsina Pankaczi, Zita Fülöp and Zsuzsanna Farkas for help in plant physiological experiments.