Towards a more sustainable viticulture: Foliar application of N-doped calcium phosphate nanoparticles on Tempranillo grapes

BACKGROUND: The use of nanomaterials for the efficient delivery of active species in viticulture is still an unexplored opportunity. Nitrogen, an essential nutrient for grapevine development and wine quality, is commonly provided in the form of urea. However, the application of conventional fertilisers contributes to nitrate leaching and denitrification, thus polluting groundwater and causing a serious environmental impact. Nanotechnology is offering smart solutions towards more sustainable and efficient agriculture. In the present work, we assessed the efficiency of nontoxic amorphous calcium phosphate (ACP) nanoparticles as nanocarriers of urea (U-ACP) through field experiments on Tempranillo grapevines. Four treatments were foliarly applied: U-ACP nanofertiliser (0.4 kg N ha–1), commercial urea solutions at 3 and 6 kg N ha–1 (U3 and U6) and a control treatment (water). RESULTS: The grapes harvested from plants treated with U-ACP and U6 provided similar levels of yeast assimilable nitrogen, despite the very large reduction of nitrogen dosage. The concentration of amino acids was greater in U-ACP-treated plants than those of the control and U3 treatments and, barring a few exceptions, the values were comparable with those observed in grapes obtained following U6 treatment. Nanofertilisers provided a high arginine concentration in the musts but low proline concentrations in comparison to the U6 treatment. CONCLUSIONS: The results of this work show the potential benefits of nanotechnology over conventional practices for nitrogen fertilisation. Significantly, the application of U-ACP allowed a considerable reduction of nitrogen dosage to maintain the quality of the harvest, thereby mitigating the environmental impact.