Nanoscale hydroxyapatite coated Cu-based nanopesticides exhibited promising benefits: Enhanced application efficiency and plants elements homeostasis

Abstract

Cu-based pesticides are popular globally due to their low toxicity, high efficiency, broad applicability, and cost-effectiveness. However, their application often leads to waste and environmental issues. Here, we developed nanoscale hydroxyapatite(HAP) as the Cu-based pesticide carrier and coated with chitosan to realize the function of Cu/P slow release. The HAP carrier with three sizes (20 nm, 60 nm, and 80 µm) and three types of Cu-based pesticides (OrganCu, InorganCu, and NanoCu) were prepared and compared. The obtained nanopesticides with 60nm HAP carrier and NanoCu commercial pesticide (K60) exhibited application potential on long-term application performance, which demonstrated a particle size of less than 200 nm. At low concentrations (10 mg/kg), NanoCu pesticides significantly affected the soil microorganism diversity. The K60 could decrease the influence on microorganism diversity compared with the original commercial pesticides, which was accounted for the alpha diversity and microbial species composition variation. Besides, the K60 enhanced the phosphorus deficiency resistance of lettuces through adjustment of microelements homeostasis. This phenomenon was accounted for by the in 5 μM K60 increasing the Cu and P uptake (77.81% and 76.12%, respectively), and increasing the Mg and K uptake in root (44.95% and 39.74%, respectively). The nanopesticides dosage contributed more influence than nanocarrier size in lettuce roots ionome variation. Our research findings emphasize sustainable strategies to enhance the utilization efficiency of commercial pesticides while mitigating ecological risks. These insights contribute valuable ideas and references for the subsequent market introduction of nanopesticides. Keywords: Cu-based nanopesticides, slow-release, hydroxyapatite, plant elements homeostasis, soil microorganism