| In 2021,702-828 million people worldwide are facing hunger,and the outbreak of the Russia-Ukraine war in February 2022 also affects the trajectory of global food security.Pesticides and fertilizers have to some extent boosted food production while overuse has directly caused soil ecological damage,disease proliferation and pesticide residues.We urgently need a new technology to cope with food shortage,pesticide and chemical fertilizer reduction,ecological restoration,etc.Nanotechnology has great potential for development,and a lot of research has been done to prove that nanomaterials can improve photosynthesis efficiency to promote plant growth,remediate soil and environmental pollution,etc.to achieve yield increase,but it is limited to the laboratory basic research stage.In the past 6 years,our team has used our self-developed MPNP macro-preparation metal nano-powder technology to prepare metal nano-powder materials,which have been demonstrated and promoted in 28provinces,municipalities and autonomous regions in China and more than 10 countries abroad for more than 80 kinds of crops,with yield increase of 24-42%.It is fully verified that nanomaterials can improve crop yield and quality,and ensure food security and nutritional status.Nanomaterials affect microorganisms in the process of use.In order to explore the coupling effect of Cu and Fe nanoparticles on harmful and beneficial bacteria in addition to their yield-enhancing effect,this thesis selects the plant harmful bacteria Fusarium tritici and beneficial bacteria Bacillus subtilis to evaluate the antibacterial effect of Cu and Fe nanoparticles on their bacterial inhibition and the actual use of Fe nanoparticles in large fields.The main studies are as follows:（1）Structural,morphological and compositional characterization of Cu and Fe nanoparticles showed that Cu and Fe nanoparticles are spherical in shape,uniform in size,well dispersed,with core-shell structure and particle size between 20-80 nm,which are suitable as nano antibacterial agents.（2）To study the coupling effect of liquid antimicrobial agents with different concentrations of Cu and Fe nanoparticles on the harmful plant fungus Fusarium trituberculatum,the results showed that the MIC of liquid antimicrobial agents with copper nanoparticles was between 10-6-5×10-6 g/m L and MBC was between 5×10-5-10-4 g/m L;the MIC of liquid antimicrobial agents with iron nanoparticles was between 10-5-5×10-5 g/m L and MBC was between 5×10-4-10-3 g/m L,which is suitable for agricultural production.（3）To study the antibacterial performance of Cu and Fe nanoparticle liquid antimicrobial agents at different concentrations against the beneficial bacteria Bacillus subtilis,the results showed that the MIC of Cu nanoparticle liquid antimicrobial agent was between 10-7-2×10-7 g/m L and MBC was between 5×10-7-6×10-7 g/m L,while the Fe nanoparticle liquid antimicrobial agent was not sensitive to the beneficial bacteria and was more suitable for agricultural promotion.（4）Foliar spraying of tomatoes with iron nanomicron fertilizer was conducted at different periods to study its ability to suppress pests and diseases,and the statistical results at the harvesting stage of the third and fifth fruit ears showed that the plant morbidity and plant mortality rates were lower than the control by 3.6-6.4%.The foliar spraying of iron nano-fertilizer at the seedling stage increased the yield by 14.97%compared with the control,and at the fruiting stage increased the yield by 7.61%compared with the control,which showed that the effect of foliar spraying at the seedling stage was better than that at the fruiting stage,and provided data to support the application of iron nano-fertilizer on tomato in a large area.（5）In the experiment of pesticide reduction on special high spicy pepper,the incidence of leaf spot disease,root rot,powdery mildew and insect and fruit rate were all slightly better than the control effect under the standard pesticide use when using Fe nanomicron fertilizer at one-third of the pesticide reduction,indicating that Fe nanomicron has excellent antibacterial properties in field crops and can promote the implementation of pesticide reduction strategy. |
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