Application of Nanofertilizer and Nanopesticides for Improvements in Crop Production and Protection

Prospects and challenges of nanopesticides in advancing pest management for sustainable agricultural and environmental service

The expanding global population and the use of conventional agrochemical pesticides have led to the loss of crop yield and food shortages. Excessive pesticide used in agriculture risks life forms by contaminating soil and water resources, necessitating the use of nano agrochemicals. This article focuses on synthesis moiety and use of nanopesticides for enhanced stability, controlled release mechanisms, improved efficacy, and reduced pesticide residue levels. The current literature survey offered regulatory frameworks for commercial deployment of nanopesticides and evaluated societal and environmental impacts. Various physicochemical and biological processes, especially microorganisms and advanced oxidation techniques are important in treating pesticide residues through degradation mechanisms. Agricultural waste could be converted into nanofibers for sustainable composites production, new nanocatalysts, such as N-doped TiO2 and bimetallic nanoparticles for advancing pesticide degradation. Microbial and enzyme methods have been listed as emerging nanobiotechnology tools in achieving a significant reduction of chlorpyrifos and dimethomorph for the management of pesticide residues in agriculture. Moreover, cutting-edge biotechnological alternatives to conventional pesticides are advocated for promoting a transition towards more sustainable pest control methodologies. Application of nanopesticides could be critical in addressing environmental concern due to its increased mobility, prolonged persistence and ecosystem toxicity. Green synthesis of nanopesticides offers solutions to environmental risks associated and using genetic engineering techniques may induce pest and disease resistance for agricultural sustainability. Production of nanopesticides from biological sources is necessary to develop and implement comprehensive strategies to uphold agricultural productivity while safeguarding environmental integrity.

Physicochemical properties and fractal characterizations of the functionalized porous clinoptilolites for controlling alginate delivery in growing cauliflower and leaf mustard

Using natural clinoptilolite (NCP) as a carrier and alginate (Alg)-calcium as an active species, the porous silicon calcium alginate nanocomposite (Alg-Ca-NCP) was successfully fabricated via adsorption-covalence-hydrogen bond. Its structural features and physicochemical properties were detailed investigated by various characterizations. The results indicated that Alg-Ca-NCP presented the disordered lamellar structures with approximately uniform particles in size of 300-500 nm. Specially, their surface fractal evolutions between the irregular roughness and dense structures were demonstrated via the SAXS patterns. The results elucidated that the abundant micropores of NCP were beneficial for unrestricted diffusing of Alg-Ca, which was conducive to facilitate a higher loading and sustainable releasing. The Ca content of leaf mustard treated with Alg-Ca-NCP-0.5 was 484.5 mg/100g on the 21st day, higher than that by water (CK) and CaCl2 solution treatments, respectively. Meanwhile, the prepared Alg-Ca-NCPs presented the obvious anti-aging effects on peroxidase drought stress of mustard leaves. These demonstrations provided a simple and effective method to synthesize Alg-Ca-NCPs as delivery nanocomposites, which is useful to improve the weak absorption and low utilization of calcium alginate by plants.

Sonication and heat-mediated synthesis, characterization and larvicidal activity of sericin-based silver nanoparticles against dengue vector (Aedes aegypti)

Fabrication, characterization and evaluation of the larvicidal potential of novel silk protein (sericin)-based silver nanoparticles (Se-AgNPs) were the prime motives of the designed study. Furthermore, investigation of the sericin as natural reducing or stabilizing agent was another objective behind this study. Se-AgNPs were synthesized using sonication and heat. Fabricated Se-AgNPs were characterized using particle size analyzer, UV spectrophotometry, FTIR and SEM which confirmed the fabrication of the Se-AgNPs. Size of sonication-mediated Se-AgNPs was smaller (7.49 nm) than heat-assisted Se-AgNPs (53.6 nm). Being smallest in size, sonication-assisted Se-AgNPs revealed the significantly highest (F4,10  = 39.20, p = .00) larvicidal activity against fourth instar lab and field larvae (F4,10  = 1864, p = .00) of dengue vector (Aedes aegypti) followed by heat-assisted Se-AgNPs and positive control (temephos). Non-significant larvicidal activity was showed by silver (without sericin) which made the temperature stability of silver, debatable. Furthermore, findings of biochemical assays (glutathione-S transferase, esterase, and acetylcholinesterase) showed the levels of resistance in field strain larvae. Aforementioned findings of the study suggests the sonication as the best method for synthesis of Se-AgNPs while the larvicidal activity is inversely proportional to the size of Se-AgNPs, i.e., smallest the size, highest the larvicidal activity. Conclusively, status of the sericin as a natural reducing/stabilizing agent has been endorsed by the findings of this study. RESEARCH HIGHLIGHTS: Incorporation of biocompatible and inexpensive sericin as a capping/reducing agent for synthesis of Se-AgNPs. A novel sonication method was used for the fabrication of Se-AgNPs which were thoroughly characterized by particle size analyzer, UV-visible spectrophotometry, SEM and FTIR. Analysis of enzymatic (GSTs, ESTs) levels in field and lab strains of Aedes aegypti larvae for evaluation of insecticides resistance.

Conventional versus Nano Calcium Forms on Peanut Production under Sandy Soil Conditions

Abiotic stresses in sandy soil, which include saline water, saline soil, and lack of nutrients, affect the productivity and quality traits of peanuts (Arachis hypogaea L). Elemental calcium (Ca2+) is necessary for the proper development of peanut pods. This work aimed at comparing conventional Ca and nano-Ca form effects on peanut production and quality traits. Two randomized complete block field experiments were conducted in the 2015 and 2016 seasons. Treatments were control, gypsum plus calcium nitrate Ca(NO3)2, Ca(NO3)2, and chelated calcium, as well as 100, 75, 50, 25, and 12.5% of Ca(NO3)2 doses in a nano form. The results indicated that the treatment of gypsum plus conventional CaNO3 achieved the highest yield and best quality traits, followed by the Ca(NO3)2 and 100% nano Ca(NO3)2 treatments. The treatments of the control, gypsum, and 12.5% nano Ca(NO3)2 had the lowest effect on peanut performance. The conventional treatment of gypsum plus Ca(NO3)2 resulted in the greatest seed yield (1.6 ton ha−1), oil yield (700.3 kg ha−1), and protein yield (380.1 kg ha−1). Peanuts may benefit from Ca2+ better by using gypsum as the soil application and calcium nitrate as the foliar application to prevent disorders of Ca2+ deficiency under sandy soil conditions.

Accumulation, speciation and localization of silver nanoparticles in the earthworm Eisenia fetida

The use of silver nanoparticles (AgNPs) in agriculture and many consumer products has led to a significant release of Ag in the environment. Although Ag toxicity in terrestrial organisms has been studied extensively, very little is known about the accumulation capacity and coping mechanisms of organisms in Ag-contaminated soil. In this context, we exposed Eisenia fetida earthworms to artificial OECD soil spiked with a range of concentrations of Ag (AgNPs or AgNO₃). The main aims were to (1) identify the location and form of accumulation of Ag in the exposed earthworms and (2) better understand the physiological mechanisms involved in Ag detoxification. The results showed that similar doses of AgNPs or AgNO₃ did not have the same effect on E. fetida survival. The two forms of Ag added to soil exhibited substantial differences in speciation at the end of exposure, but the Ag speciation and content of Ag in earthworms were similar, suggesting that biotransformation of Ag occurred. Finally, 3D images of intact earthworms obtained by X-ray micro-computed tomography revealed that Ag accumulated preferentially in the chloragogen tissue, coelomocytes, and nephridial epithelium. Thus, E. fetida bioaccumulates Ag, but a regulation mechanism limits its impact in a very efficient manner. The location of Ag in the organism, the competition between Ag and Cu, and the speciation of internal Ag suggest a link between Ag and the thiol-rich proteins that are widely present in these tissues, most probably metallothioneins, which are key proteins in the sequestration and detoxification of metals.

Effect of zeolites on soil modification and productivity

Local natural zeolite-containing rocks use efficiency in agriculture of the Republic of Tatarstan was studied in the research. The research was conducted in the field on leached black soil applying mechanoactivated zeolites and in greenhouses on grey forest soil using nanostructured zeolite. Field experiments identified the soil deacidification of 0.4 pHsol, increase of assimilable phosphates of the 1st and 2nd groups (Ca-P1 и Ca-P2) – of 5.0 and 6.6 mg per 100 g of soil. Moreover, the research considered the increasing the mobile phosphorus available to plants – of 8.0 and 10.0 mg/kg and exchange potassium of 5.0 and 6.6 mg/kg according to the doses of zeolite of 10 and 15 t/ha. Improving the activity of microflora in rhizosphere and growth acceleration of microbial biomass to 15.5 mg per 100 g*h were observed. The average annual grain yield gain was 0.3 and 0.5 t/ha, and the payback of 1 ton of zeolite by additional harvest 0.11 and 0.09 t/ha in grain units respectively. Improvement in the reaction of the soil environment was stated in the vegetative conditions on gray forest soil using nanostructured zeolite in doses of 0.1 and 1.0 t/ha, a positive shift in pHsol, was 0.97 and 0.9 units respectively. Under the influence of mechanically activated celite at a dose of 15 t/ha, soil acidity decreased by 0.99 pHsol units. The use of nanostructured zeolite contributed to an increase of the reserves of ammonia nitrogen in the soil – by 0.8 and 2.4 mg/kg, mobile phosphorus – by 6.0 and 33.0 mg/kg, and exchangeable potassium – by 3.0 and 5.5 mg/kg respectively at doses of 0.1 and 1.0 t/ha respectively. The growth of microbial biomass was up to 24.0 mg/100 g*h. Additional grain gains were obtained: under the influence of mechanically activated zeolite at a dose of 15 t/ha – 8.6 g/vessel and nanostructured analog at a dose of 0.1 t/ha – 7.3 g/vessel, which were comparable at the consumption of the latter 150 times less.

Nanoparticle-Plant Interactions: Two-Way Traffic

In this Review, an effort is made to discuss the most recent progress and future trend in the two-way traffic of the interactions between plants and nanoparticles (NPs). One way is the use of plants to synthesize NPs in an environmentally benign manner with a focus on the mechanism and optimization of the synthesis. Another way is the effects of synthetic NPs on plant fate with a focus on the transport mechanisms of NPs within plants as well as NP-mediated seed germination and plant development. When NPs are in soil, they can be adsorbed at the root surface, followed by their uptake and inter/intracellular movement in the plant tissues. NPs may also be taken up by foliage under aerial deposition, largely through stomata, trichomes, and cuticles, but the exact mode of NP entry into plants is not well documented. The NP-plant interactions may lead to inhibitory or stimulatory effects on seed germination and plant development, depending on NP compositions, concentrations, and plant species. In numerous cases, radiation-absorbing efficiency, CO2 assimilation capacity, and delay of chloroplast aging have been reported in the plant response to NP treatments, although the mechanisms involved in these processes remain to be studied.