Nanofertilizers: An innovative solution to boost production and reduce environmental impact

Nanofertilizers improve fertilization efficiency and help mitigate the effects of climate change

Context of the story

Traditional agricultural production is costly for the farmer and generates negative effects on the environment due to the low efficiency of fertilization, since crops absorb only between 20% and 40% of the fertilizer. This results in a waste of inputs and a loss of profitability for the farmer, who incurs high investment costs in fertilizers that do not achieve a proportional increase in crop yield. An alternative solution to this situation is the implementation of nanotechnology, as it enables the development of sustainable agriculture with both environmental and economic benefits for the farmer, by improving nutrient absorption efficiency and reducing the amount of fertilizer required per hectare.

The Implemented Initiative

Assess the effect of applying blends of fertilizers and nanofertilizers (zeolite, titanium dioxide, and zinc oxide) on the intensive production of crops. For this, a process of nanostructuring and characterization of TiO2, ZnO and zeolite nanofertilizers is being developed, through the high-energy mechanical grinding technique, using a planetary mill. The nanostructured material is implemented in experimental plots on corn producers' properties. The tests allow phytotoxicity tests to be carried out, evaluate the effects on productivity and estimate the impacts generated on the soil’s physical, chemical, and biological characteristics.

Using balanced fertilizers and nanofertilizers in crops increases biomass production and nitrogen absorption.

The technological solution

The project produced titanium dioxide (TiO₂), zinc oxide (ZnO) and zeolite nanoparticles by high-energy milling, a method that uses no reagents and leaves no chemical waste, with particle size controlled by varying the mill's fill factor, milling time and speed. The nanoparticles were combined with balanced fertilizers, formulated to match soil supply and crop requirements, so that plants make better use of the nitrogen applied. Their safety was assessed through phytotoxicity bioassays, and their effects on soil, biomass, forage quality, drone-measured spectral response and nitrous oxide and carbon dioxide emissions were tested on ryegrass in the greenhouse and on maize and kikuyu grass in the field, in Colombia and Ecuador. The project also designed a spin-off company to produce and market the nanofertilizers.

"Nitrogen use efficiency globally ranges between 30 to 50% depending on the forage species, generating economic losses in nitrogen fertilization."

— Dobermann, A. (2007). Nutrient use efficiency-measurement and management. Proc. Of International Fertilizer Industry Association (IFA) Workshop on Fertilizer Best Management Practices. Brussels, Belgium. March 7-9.

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Type of project

Agronomic Practices

Applied

Technological

Results

The nanoparticles reached average sizes below 150 nm without altering their crystal structure, and bioassays set concentrations below 3% as safe. In ryegrass, adding zinc oxide or zeolite to the fertilizer raised nitrogen recovery efficiency (the share of applied nitrogen taken up by the crop) from 63% to 95.5% and 89%, respectively; 8 g of fertilizer plus nanoparticles produced more dry biomass than 12 g without them, and nitrous oxide emissions fell by up to 62%. Zeolite improved the soil's capacity to retain nutrients and moisture. In maize, with titanium dioxide each kilogram of nitrogen applied yielded 34.8 kg of additional grain, compared with 25.3 kg under conventional fertilization. The financial assessment confirmed the viability of the AgroNano spin-off, and the project trained 23 students and published two scientific articles.

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