Nano-fertilizers and Nano-pesticides as Promoters of Plant Growth in Agriculture. In: Singh P, Singh R, Verma P, Bhadouria R, Kumar A, Kaushik M, editors. Plant-Microbes-Engineered Nano-particles (PM-ENPs) Nexus in Agro-Ecosystems. Cham: Springer International Publishing; 2021. pp. 153-63. [DOI: 10.1007/978-3-030-66956-0_10]

Metal-based-oxide nanoparticles assisted the in vitro culture growth of Populus alba as micronutrients: essential metabolic processes and genetic stability

The present study evaluates the in vitro culture growth rate of Populus alba upon using nano metal-based-oxides such as hematite (Fe₂O₃ NPs), zinc oxide (ZnO NPs), and manganese oxide (Mn₂O₃ NPs) nanoparticles as analogues of three primary micronutrients such as iron (Fe), zinc (Zn), and manganese (Mn), which exist in soil as micronutrients. Herein, the in vitro culture growth rate was investigated using three different concentrations (i.e., 20, 40, and 60 mg L^-1) of as-prepared metal oxide nanoparticles compared to the control. In addition, the as-prepared nanoparticles have been prepared via the co-precipitation method. Furthermore, the physicochemical properties were investigated using transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and dynamic light scattering techniques. Overall, a significant difference in the biomass production-related parameters such as fresh weight, shoot length, and root length was observed compared to the control upon the treatment with micronutrient-based nano-metal-oxides (i.e., Mn₂O₃ > Fe₂O₃ > ZnO NPs, respectively). In addition, a significant increase in the root number of Populus alba plants upon their treatment with ZnO NPs was observed compared to other prepared nano-metal-oxides and the control. Also, a remarkable increase in the chlorophyll index was monitored upon the treatment with Fe₂O₃ NPs rather than the other commonly used Mn₂O₃ and ZnO NPs, respectively. Moreover, RAPD-PCR bioassays were applied, and the actual six primers showed a genetic variation percentage of 34.17%, indicating that Populus alba is highly genetically stable even in highly contaminated soil. As a result, our findings suggest an idea that indicates the ability to enhance the in vitro culture growth rate of Populus alba plants using metal oxide nanoparticles as analogous to essential micronutrients.

Novel Materials for Urban Farming

Scarcity of natural resources, shifting demographics, climate change, and increasing waste are four major challenges in the quest to feed the exploding world population. These challenges serve as the impetus to harness novel technologies to improve agriculture, productivity, and sustainability. Urban farming has several advantages over conventional farming: higher productivity, improved sustainability, and the ability to provide fresh food all year round. Novel materials are key to accelerating the evolution of urban farming - with their ability to facilitate controlled release of nutrients and pesticides, improved seed health, substrates with better water retention capability, more efficient recycling of agricultural waste, and precise plant health monitoring. Materials science enables environmental sustainability and higher harvest yields in urban farms. Here, Singapore is used as an example of a land-scarce city where urban farming may be the solution for future food production. Potential research directions and challenges in urban farming are highlighted, and how material optimization and innovation drive the development of urban farming to meet national and global food demands is briefly discussed. This review serves as a guide for researchers and a reference for stakeholders of urban farms, policy makers, and other interested parties.

Can Nanofertilizers Mitigate Multiple Environmental Stresses for Higher Crop Productivity?

The global food production for the worldwide population mainly depends on the huge contributions of the agricultural sector. The cultivated crops of foods need various elements or nutrients to complete their growth, and these are indirectly consumed by humans. During this production, several environmental constraints or stresses may cause losses in the global agricultural production. These obstacles may include abiotic and biotic stresses, which have already been studied in both individual and combined cases. However, there are very few studies on multiple stresses. On the basis of the myriad benefits of nanotechnology in agriculture, nanofertilizers (or nanonutrients) have become promising tools for agricultural sustainability. Nanofertilizers are also the proper solution to overcoming the environmental and health problems that can result from conventional fertilizers. The role of nanofertilizers has increased, especially under different environmental stresses, which can include individual, combined, and multiple stresses. The stresses are most commonly the result of nature; however, studies are still needed on the different stress levels. Nanofertilizers can play a crucial role in supporting cultivated plants under stress and in improving the plant yield, both quantitatively and qualitatively. Similar to other biological issues, many open-ended questions still require further investigation: Is the right time and era for nanofertilizers in agriculture? Will the nanofertilizers be the dominant source of nutrients in modern agriculture? Are nanofertilizers, and particularly biological synthesized ones, the magic solution for sustainable agriculture? What are the expected damages of multiple stresses on plants?

Modeling pesticides in global surface soils: Exploring relationships between continuous and discrete emission patterns

Continuous pesticide emission at constant rate does not occur in reality, but can be a useful and simple concept in modeling studies. To explore the relationship between continuous and discrete emission patterns, we introduced a simple equivalent approach based on a comparison of simulated surface soil pesticide concentrations. The simulated results indicate that, at high soil pesticide dissipation rates and low emission frequencies, the average concentrations under the continuous and discrete emission scenarios were very similar. We demonstrated that the continuous emission model that used the simple average method to calculate the emission rate always overestimated the simulated pesticide concentrations in the surface soil compared to the discrete emission model when using a one-year period based on agricultural practices. In addition, we incorporated the equivalent approach into the USEtox model (a screening-level tool), which can approximate the average pesticide concentrations in surface soil using the time-integrated fate factors at different emission frequencies. The results indicate that the continuous-emission simulations agree with the discrete emission for at least 90% of the selected pesticides based on annual or semi-annual emission patterns. Further studies into other topics, such as random emission patterns and simulation periods, are required to improve the model. Nevertheless, the equivalent approach presented in this study can aid in transforming discrete emission patterns into continuous-emission-based models and improve surface soil pesticide management.