The effect of nanoparticles on soil microorganisms and crops


For a number of years, nanoparticles have increasingly been considered to optimize pesticides and fertilizers. Together with his team, Thomas Bucheli investigated the effects on crops of two types of such nanoparticles on crops and their effect on microorganisms.

Background (completed research project)

In the past decade, nanoparticles have increasingly been analysed for their potential to make pesticides and fertilizers more effective. Their behaviour and impact on the agricultural environment as well as the associated risks were hitherto largely unknown. There was a lack of methods to detect nanoparticles in soils, micro-organisms and bacteria or data showing how the nanoparticles are distributed in the soil, their effect on soil microorganisms, the extent to which they are absorbed by plants and the consequences of this. Thomas Bucheli and his team investigated the effects of titanium dioxide (TiO2) nanoparticles and carbon nanotubes (MWCNT) - two nanoparticles that might be used in the future in agriculture on wheat and red clover. The plants were grown in pots with natural soil or in a liquid substrate (hydroponics) and the nanoparticles were added in increasing concentrations. In addition to the effect of the nanoparticles on the plants themselves, the researchers also studied the effects on nitrogen (N)-fixing nodule bacteria (R. trifolii) and phosphorus-producing mycorrhizal fungi, both of which coexist in close symbiosis with wheat and red clover and provide the plants with vital nutrients.


In liquid cultures, the researchers were able to show that TiO2, at elevated concentrations, can disturb the symbiosis between clover and bacteria and have a negative impact on the growth of clover. In natural soil, the mobility of the nanoparticles was weak and no increase in the uptake of titanium dioxide by the plants was found. Although the mobility of MWCNT in soils was also weak, the experiments showed a concentration-independent uptake of MWCNT by the plants and a reduction in the number of red clover blossoms in the case of high concentrations. Both TiO2 and MWCNT in very high concentrations resulted in a change in the composition of the microbial communities that interact with the plants.


This project provides initial data for an improved assessment of the effect of TiO2 and MWCNT. Effects on plants and on the microbial composition of soils only occurred in high concentrations. Further data is required to assess the benefits and risks of these nanoparticles for agricultural use. The report of this project provides an overview of the current situation, intended applications, and proposes research priorities. It was presented internationally at meetings and conferences and attracted a great deal of interest.

Original title

Effects of NANOparticles on beneficial soil MIcrobes and CROPS (NANOMICROPS)

Project leader(s)

  • Dr. Thomas Daniel Bucheli


  • Dr. Katja Knauer
  • Dr. Marcel Van der Heijden
  • Dr. Franco Widmer



Further information on this content


Dr. Thomas Bucheli Forschungsanstalt Agroscope Reckenholz-Tänikon Reckenholzstrasse 191 8046 Zürich +41 44 377 73 42