Nanotechnology, which involves manipulating matter at the atomic and molecular scales to produce structures and devices ranging from 1 to 100 nm, is increasingly being applied in agriculture. Nanoscale materials possess distinct optical, electrochemical, and mechanical properties that enable the smart, targeted delivery of pesticides, fertilizers, and genetic materials to plants, as well as rapid sensing and on-site monitoring of plant health, soil fertility, and water quality in a digital format. This review explores the application of nanotechnology in agriculture, examining the challenges and benefits related to all aspects of crop production, with a particular focus on regulatory issues. Key findings indicate that nanotechnology can improve crop production and reduce the environmental footprint of agriculture through precise input management. However, several critical issues need to be addressed, including the limited knowledge of the long-term environmental impacts associated with agricultural nanotechnology and the ambiguity of current regulations. This underscores the need for further research to elucidate its impact on soil, water, and environmental and human health, to inform evidence-based regulations. (c) 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Phosphorus (P) is a crucial macronutrient for plant growth, root development, and yield. Commercial P fertilizers have low efficiency of delivery and utilization and are lost from plant root zones by either low availability or leaching or surface runoff that leads to environmental damage. This review investigates how nano P fertilizers (NPFs) can overcome the current inefficiencies of conventional formulations and, thus, enhance plant yield while minimizing negative environmental impacts. NPFs have significant potential for augmenting plant germination by more effectively penetrating seed coatings and facilitating greater water and nutrient uptake. The nanoscale nature of NPF also uniquely facilitates greater P absorption by roots, which in turn enhances chlorophyll synthesis, improves light absorption, and optimizes electron transport efficiency-key factors in boosting plant photosynthesis. Additionally, it stimulates overall physiological processes (e.g., secondary metabolite production, root exudation), increases antioxidant enzyme activities, and enhances plant yield. NPFs can also minimize the accumulation of toxic elements by several mechanisms, including controlling contaminant bioavailability in soil by enhancing competing plant essential element (e.g., P, Ca) uptake. Moreover, NPFs also mediate soil pH, which has important implications for soil biogeochemistry in low-pH agricultural areas. Soil microbiomes and associated processes will often improve with NPF application relative to conventional P formulations. Although great potential has been demonstrated, a mechanistic understanding of certain aspects of NPF activity remains incomplete, including impacts across diverse crop species, environmental conditions, and soil types. However, NPFs offer great potential as an important tool in the transformation of conventional agriculture, simultaneously lessening the usage of finite P resources, reducing the environmental footprint of agriculture, and improving future food security.

Nitrogen fertilizers have a significant impact on the growth of rice. The overuse and inappropriate application of nitrogen fertilizers have resulted in environmental pollution, in addition to subjecting both humans and livestock to negative health hazards. Finding a viable substitute for traditional nitrogen fertilizers is crucial and essential to help improve crop yield and minimize environmental damage. Nano-nitrogen fertilizers offer a possible alternative to traditional fertilizers due to a slow/controlled release of nitrogen. The present work aimed to study the effect of a slow-release urea nanofertilizer on soil ammonical (NH4-N) and nitrate-N (NO3-N) content, culturable soil microflora, and soil enzyme activities in three different soil samples procured from Ludhiana and Patiala districts through a soil column study. Seven treatments, including 0, 50 (75 kg/ha N), 75 (112.5 kg/ha N), and 100% (150 kg/ha N) of the recommended dose (RD) of conventional urea and nano-urea fertilizer were applied. The leachate samples collected from nano-urea treatment exhibited NH4-N for the first two weeks, followed by NO3-N appearance. The higher NH4-N and NO3-N contents in the leachate were recorded for light-textured soil as compared to medium- and heavy-textured soil samples. The soil microbial counts and enzyme activities were recorded to be maximum in light-textured soils. Therefore, this slow-release formulation could be more useful for light-textured soils to decrease applied N-fertilizer losses, as well as for improving the soil microbial viable cell counts and soil enzyme activities. The effect of urea nanofertilizer on the growth and yield of direct-seeded rice (Oryza sativa L.) was also evaluated under field conditions. Both studies were performed independently. Numerically, the highest shoot height, fresh and dry shoot weight, and significantly maximum total chlorophyll, carotenoid, and anthocyanins were recorded in the T2 (100% RDF through nano-urea) treatment. The yield-attributing traits, including the number of filled grains and thousand-grain weight, were also recorded to have increased in T2 treatment. A numerical increase in NPK for plant and grain of rice at 100% RDN through nano-urea was recorded. The soil application of the product exhibited no negative effect on the soil microbial viable cell count on different doses of nano-urea fertilizer. The soil nitrogen fixer viable counts were rather improved in nano-urea treatments. The results reflect that nano-urea fertilizer could be considered as a possible alternative to conventional fertilizer.

Fertilizers play a crucial role in enhancing the productivity of plants. However, low nutrient use efficiencies of conventional fertilizers (CFs) associated with several losses have led to widespread multi-nutrient deficiencies in the soil and lower productivity. Furthermore, their excess application has caused serious damage to the soil and environment. Recently, nanotechnology has broadened its applicability in plant nutrition and has paved a way for the production of nanoparticle-induced fertilizers. Therefore, nanofertilizers stand out as promising alternative to CFs for sustainable agriculture. Nanofertilizers are composed of nanoparticles that contain macro- and micronutrients and deliver them in a controlled way to the plant's rhizosphere. This contributes to the enhanced nutrient utilization efficiency. This review delves into the effect of nanotechnology-based nanofertilizers in different forms and dosages on soil properties and plant development. Additionally, the mechanism underlying absorption of nanofertilizers and their advantages and limitations have also been discussed. A thorough comparison between conventional and nanofertilizers has also been made in this review in terms of their nutrient delivery mechanism, efficiency and application. As the use of nanoparticle-embedded fertilizers in plant nutrition is still in its infancy, this review can serve as a guide for future investigations to enhance the knowledge of the use of nanoparticles in the mineral nutrition of different crops.

The widespread proliferation of water hyacinth (Eichhornia crassipes) in aquatic ecosystems has raised significant ecological, environmental, and socioeconomic concerns globally. These concerns include reduced biodiversity, impeded water transportation and recreational activities, damage to marine infrastructure, and obstructions in power generation dams and irrigation systems. This review critically evaluates the challenges posed by water hyacinth (WH) and investigates potential strategies for converting its biomass into value-added agricultural products, specifically nanonutrients-fortified, biochar-based, green fertilizer. The review examines various methods for producing functional nanobiochar and green fertilizer to enhance plant nutrient uptake and improve soil nutrient retention. These methods include slow or fast pyrolysis, gasification, laser ablation, arc discharge, or chemical precipitation used for producing biochar which can then be further reduced to nano-sized biochar through ball milling, a top-down approach. Through these means, utilization of WH-derived biomass in economically viable, eco-friendly, sustainable, precision-driven, and smart agricultural practices can be achieved. The positive socioeconomic impacts of repurposing this invasive aquatic plant are also discussed, including the prospects of a circular economy, job creation, reduced agricultural input costs, increased agricultural productivity, and sustainable environmental management. Utilizing WH for nanobiochar (or nano-enabled biochar) for green fertilizer production offers a promising strategy for waste management, environmental remediation, improvement of waterway transportation infrastructure, and agricultural sustainability. To underscore the importance of this work, a metadata analysis of literature carried out reveals that an insignificant of the body of research on WH and biochar have focused on the nano-fortification of WH biochar for fertilizer development. Therefore, this review aims to expand knowledge on the upcycling of non-food crop biomass, particularly using WH as feedstock, and provides crucial insights into a viable solution for mitigating the ecological impacts of this invasive species while enhancing agricultural productivity.

High bicarbonate concentration in the soil induces iron (Fe) deficiency in fruit trees. According to the promising performance of nanomaterials in supplying mineral nutrients, in this study the potential of 4 green synthesized Fe nano-complexes (Fe-NCs) on alleviating bicarbonate stress in almond trees was evaluated in a soilless culture. The Fe-NCs were formed on extracts of husks of almond, pistachio, walnut, and pomegranate and their efficiency in Fe supply was compared to a commercial FeEDDHA fertilizer. The bicarbonate stress was imposed by adding sodium bicarbonate + calcium carbonate to the Hoagland's nutrient solution: Control (without sodium bicarbonate + calcium carbonate); 10 mM NaHCO3+5 mM CaCO3; 20 mM NaHCO3+10 mM CaCO3. The plants were irrigated with nutrient solutions containing different concentrations of bicarbonate and different sources of Fe for 120 days. Bicarbonate stress induced chlorophyll decline, proline accumulation and leaf necrosis, and decreased leaf area. These responses were in line with decline in Fe concentration and development of oxidative damage in leaves, as hydrogen peroxide accumulation and membrane stability index decline were observed in the bicarbonatestressed plants. Although walnut-nFe and pistachio-nFe intensified these adverse effects of bicarbonate stress, the almond-nFe and pomegranate-nFe recovered chlorophyll concentration, alleviated the oxidative damage, and restored Fe in the plants to the range of FeEDDHA under bicarbonate stress. Alleviating the damages was related to retrieving the concentration of proteins, hydrogen peroxide detoxification, and catalase activity in the leaves. These findings uncovered the potential of green synthesized almond-nFe and pomegranate-nFe as low-cost and effective Fe sources under bicarbonate stress.