**8. Effect of nanomaterials on soil/plant systems**

Nanotechnology has opened up new avenues for increasing nutrient efficiency and lowering environmental protection expenditures. The fact that fertilizer usage efficiency is just 20–50% for nitrogen and 10–25% for phosphorus is alarming [95]. According to researchers [96], the introduction of nanofertilizers as an alternative to traditional fertilizers would remove nutrient buildup in soils, therefore eliminating eutrophication and drinking water pollution. The main idea is to improve the efficiency of native and applied phosphorus in soils to keep the ratio of applied and plant absorption P near unity. Because nearly all P fertilizers contain heavy metals and, more significantly, deliver P to plants in accessible forms, there is a need to regulate critical and harmful components linked with phosphorous in the pedosphere–hydrosphere continuum. Nanofertilizers increased the quality of agricultural goods, eliminated environmental risks, and needed less fertilizer than conventional fertilizers [97]. Because the rate of release of absorbed nitrogen (or fertilizers compounds) is much slower than that of adsorbed ionic forms of nitrogen, zeolites could be used for nitrogen capture and storage [98]. Researchers [99] noticed that zeolite chips containing urea in their cavities can be used as a slow-release nitrogen fertilizer material. When zeolites were loaded with nitrogen,

#### *Potential Applications of Nanotechnology in Agriculture: A Smart Tool for Sustainable Agriculture DOI: http://dx.doi.org/10.5772/intechopen.101142*

potassium, phosphorous, calcium, and a set of minor and trace nutrients, few researchers [100] discovered that the honeycomb-like layered crystal network slowly released nutritional ions "on demand."

According to another researcher [101], application of a nanocomposite comprising N, P, K, certain micronutrients, mannose, and amino acids improved nutrient absorption in grain crops. A group of researchers [41] used zinc–aluminum layered double-hydroxide nanomaterials with plant growth regulators and discovered that the products released chemicals in a regulated way. These studies showed that nanotechnology may be used to build advanced supply tools with great success. There are carbonaceous chemicals that are secreted into the soil that allow N and/or P mineralization from organic matter and P mineralization from soil inorganic colloids in nutrient-depleted soils. As environmental signals, these root exudates may be utilized to make nanobiosensors, which could then be integrated into new nanofertilizers, according to the authors' hypothesis.

It's well-known that current fertilizers create soil acidity, alter soil carbon profiles, harm beneficial microorganisms, weather clay minerals, and collect heavy metals in the soil. As receptacles, novel nanofertilizers use plant-nutrient ions intercalating or adsorbing on clay minerals. Salts make up the majority of current fertilizers, with one component consisting of plant-nutrient ion(s), whereas the other component isn't particularly beneficial or harmful at all. To enhance soil structure, reduce salt concentration, and promote crop development in salt-affected soils, nanotechnology can be utilized to improve soil structure. The following are some areas where research might be initiated: CaCO3 solubilization, Na2CO3 prevention, adding K+ to clay minerals, and increasing precipitation are all examples of ways to reduce salt concentration in soil solution, improve drainage, and/or replace Na + with Ca2+ and/or K+.

In order to determine the influence of nanoparticles on soil microbial activity, soil respiration and enzymatic activity must be measured. Soil enzymatic activity and bacterial abundance may be affected by metallic nanoparticles [102]. They can also cause free radical damage to bacteria' cell membranes, DNA and mitochondria. Even beneficial microorganism communities may be threatened by the introduction of nanoparticles (NPs) into the natural environment. In flooded paddy soil, TiO2 and CuO nanoparticles reduced soil microbial biomass and enzymatic activity, as well as their community structure. Increased Fe3O4 nanoparticle concentration dramatically reduced the number of bacteria in soil, and produced cavities, holes and membrane breakdown in the microorganisms [103].

*Bipolaris sorokiniana* and *Magnaporthe grisea* were exposed to silver ions and silver nanoparticles to determine their effects [104]. These treatments effectively inhibited colonization of both fungi, with an EC50 much lower than the ionic Ag treatments. Scientists have demonstrated antibacterial activity of Ag nanoparticles and polyvinylpyrrolidone (PVP) against three types of bacteria [105]. Researchers have shown that Zinc oxide nanoparticles (ZnO NP) are as antibacterial as silver nanoparticles (AgNPs). Sulfur dioxide (ZnO) was typically more toxic to bacteria in the Gram-positive group than the Gram-negative group. *Staphylococcus aureus* was treated for 8 hours, and *Salmonella typhimurium* for 4 hours [106]. When it came to *Botrytis cinerea* and *Penicillium expansum* colonization, the S NPs (35 nm) were shown to be more efficient than the larger particles.

#### **9. Nanomaterials to mitigate environmental stresses in plants**

Plants are sessile organisms and undergo abiotic stressors that impact their development and production throughout their life cycle. In response to environmental stressors, plants generate defensive mechanisms at multiple levels through modification of their biochemical and morphological routes as well as their molecular pathways (the changing of genetic expressions). But these are not sufficient to annul all the adverse effects of environmental stress. The salinity reduces, for example, the osmotic potential of the soil, resulting in food disequilibrium. Improve ionic toxicity negatively impacts many important biochemical or physiological activities including photosynthesis, protein synthesis and lipid metabolism. The rising world population and the concomitant decline in food supply, with ongoing environmental changes, are currently in a difficult state. Therefore, scientists' main focus is to develop strategies to expedite the plant adaptation to environmental changes.

In the worldwide scenario, salt stress alone reduces crop yield by roughly 23 per cent according to current agricultural practices. In previous study on nano-SiO2 treatment on tomatoes and squash plants, there have been numerous beneficial results on the usage of nano fertiliser in salty circumstances [107, 108]. The use of silica nanoparticles increases plant tolerance to drought stress by promoting plants' agronomic parameters, physiology, biochemistry, delay senescence, and maintained water status of plants exposed to the water-deficit condition [109, 110]. *Crataegus sp*. has enhanced dryness tolerance with varied concentrations of silica nanoparticles, changing their physiological and biochemical processes [111]. Researchers think that growing agricultural plants with shorter life cycles is particularly efficient in areas susceptible to drought or flash-flood here early crop maturation is a critical component for sustained crop output [112]. Studies revealed that the life cycle of the wheat crop used in nano fertilizers is considerably shorter than the traditional wheat crop used in fertilizers, which is 130 days compared with 170 days (date of sowing to yield production) [113].

Although several investigations of the use of nanomaterials to plant development have been carried out during stress environments, the fundamental components remain mostly unexplored. However, researchers believe that, under unfavorable environmental circumstances, the impacts of nanomaterials on crop development are partially attributable to the enhanced enzyme activity. The activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) are regulated by nanoparticles [114]. Increased SOD activities have been observed by the application of TiO2 nanoparticles on onion seedlings [115]. At lower levels of TiO2 the activity of the enzyme is greater. The buildup of free proline and amino acids is escalating by nanomaterials (nano-SiO2 and nano-ZnO). The consumption of nutrients and water might also rise. The use of these nanoparticles further enhances the activity of the antioxidant enzymes such as SOD, CAT, POD and reductase nitrates. Nanomaterials can also control the expression of stress genes. For example, microscope research showed that silver nanoparticles in *Arabidopsis* can regulate a number of genetic expressions [116]. These genetic responses, which are produced by nanomaterials, are therefore directly related to plant stress defense.

## **10. Nanomaterials in plant defense mechanisms**

Plants represent the boundary between the environment and the biosphere, thus understanding how nanomaterials influence them is crucial for ecological evaluations and assessments of environmental impact. Terrestrial plants can be threatened by metal-based nanoparticles (NPs); yet, little is known about plant defense systems that could combat nanotoxicity. When cells are subjected to nanoparticles and oxidative pressure develops, the equilibrium between cell function as well as antioxidative defense systems is altered. A group of researchers [3] described

*Potential Applications of Nanotechnology in Agriculture: A Smart Tool for Sustainable Agriculture DOI: http://dx.doi.org/10.5772/intechopen.101142*


#### **Table 1.**

*Nanoparticles and its mode of action.*

cell membrane damage due to oxidative stress, as well as DNA degradation are all caused by biochemical factors that produce unnecessarily high reactive oxygen species (ROS). Different defensive mechanisms can be triggered by plants in response to stress [117]. As an example, using nanoparticles to boost plant defenses is one of the most intriguing aspects of this technology (**Table 1**). An enzyme and a non-enzymatic agent are used in plants' antioxidant defense system. These agents include SOD, CAT, APX, ascorbate peroxidase (APX), and glutathione reductase (GRT) (GR).

It has been demonstrated that nanoparticles of cerium oxide imitate enzymes for scavenging. This feature increases the plant's defensive system. As a result, microbial pathogens are prevented from completing their life cycle by multiwalled carbon nanotubes (MWCNTs). Changes in enzymes are prevalent as a result of fluctuations in ROS levels [126]. ROS play a major role in the start of plant disease resistance responses, since they are essential signals for resolving defensive gene installation. To further understand plant defense mechanisms against nanoparticles, more research is needed.

#### **11. Nanotechnology in food industry**

Food production must double by 2050 to satisfy the demands of the world's increasing population, food production must double by 2050, and new strategies are needed to fight hunger [127]. The rising global human population has resulted in a larger population to feed, and agricultural production has not kept pace with this growth. This imbalance has shown the actual need for food preservation for food items to reach people worldwide. The establishment of nanotechnology in the food sector has made it easier for food to be transported to various areas globally by increasing most food items' shelf life. The latest developments in nanostructured materials that significantly affect the food sector are novel methods in food nanotechnology (**Table 2**). Nanotechnology in today's food sector has played a significant role in food processing, food packaging and food preservation. Many areas of food science have been revolutionized by the fast growth of nanotechnology,


#### **Table 2.**

*Current uses of nanotechnology in food industry.*

particularly those involving food processing, packaging, storage, transportation, functioning, and other safety concerns. A wide range of nanostructured materials (NSMs), from inorganic metal, metal oxides, and their nanocomposites to nanoorganic materials with bioactive agents, has been applied to the food industry. **Figure 2** shows the application of nanotechnology in the food business [136].

#### **12. Nanomaterials for recycling agricultural waste**

Demand for agricultural goods is rising rapidly as the population grows. More food items are being produced to satisfy this increasing demand, resulting in a rise in waste materials. Waste is a significant issue throughout the globe, and it is produced by a variety of agricultural, industrial, and urban activities. Agricultural wastes are such kinds of wastes derived from various agricultural activities, including processing raw agricultural products; plant debris; excessive use of pesticides and fertilizers that enter into our ecosystem; wastes from animal farms and slaughterhouses; salt and silt drained from fields and finally harvest wastes. In other words, these are leftovers from the production and processing of raw agricultural goods, including fruits, vegetables, meat, poultry, dairy products, and crops [137]. Large amount-of agricultural wastes are generated every year throughout the world that can be solid, liquid, or slurries in form depending on the agricultural activities, posing a threat to the environment (**Table 3**). We are exploiting our environment using excess amounts of agrochemicals like pesticides and fertilizers every year.

*Potential Applications of Nanotechnology in Agriculture: A Smart Tool for Sustainable Agriculture DOI: http://dx.doi.org/10.5772/intechopen.101142*

**Figure 2.**

*Application areas of nanotechnology in food industry [135].*


#### **Table 3.**

*Classification of waste as per their source of origin [138].*

These chemicals are generally persistent and have a significant impact on the environment as well as human health due to the bioaccumulation in food. For sustainable agriculture, we badly need an efficient way to properly use agricultural inputs and reduce these wastes to minimize environmental pollution. Through nanotechnology, pesticides and fertilizers can be converted and reused. Some nanomaterials for the remediation of soil polluted by agrochemicals are encapsulated and slow released fertilizers and pesticides under specific conditions; controlled release of plant growth hormones and concentration of ammonium nanoparticles that can be recycled as fertilizer [139, 140].

Photocatalysis applications, coupled with nanotechnology, offer effective results and enormous possibilities for the reduction of certain harmful chemicals from

various herbicides, bactericides, and fungicides (**Table 4**). For example, for the elimination of pesticide residues from water, therefore decontamination of water is effective with the process of photocatalysis coupled to a nanomaterial [153]. On the other hand, nano-sensors can detect various chemicals and toxic pollutants that are harmful to humans. The application of nanomaterials coupled to specific antibodies can generate lights that can be used to identify and quantify agrochemicals like pesticides and fertilizers [139].

Apart from this, rice husk, a by-product from rice-mill, can be an excellent source for nano-silica production, making glass materials and concrete. This renewable nano-silica ultimately reduces the rice husk disposal problem through nanomaterials. Waste from the cotton industry, such as cellulose or other low valued products like yarns and cotton balls, can be reduced with nanomaterials' help. For example, with the use of electrospinning and newly developed solvents, 100 nm-sized fibers can be produced and use as an absorbent of various fertilizers or pesticides, which is useful for targeted application at the desired time as well as location [154, 155]. Nanocellulose can be extracted from the residues of banana cultivation like pseudostem, foliar parts, and shells, which will be the replacement of certain synthetic fibers. On the other hand, gold nanoparticles, which are numerously used in semiconductors and bio-medical areas, can be synthesized from agricultural wastes of grape seed, skin, and stalks [140, 156].

From the last couple of years, the production of ethanol from maize feedstock has increased the global price and demand of maize, and researchers are working on various nano-engineered enzymes that authorize simple and cost-effective modification of cellulose into ethanol from waste plant parts [131]. Nanomaterials also inspire the metabolism of microorganisms like the efficacy of lipid extraction can be improved with the help of nanotechnology without disrupting the microalgae. Nanomaterials like calcium and magnesium oxide nanoparticles can be used successfully as biocatalyst transporters for the transesterification of oil to bio-diesel [157].


Due to the mass production of agricultural goods, many wastes are generated every year from this sector, and with the application of nanomaterials,

#### **Table 4.**

*Nanomaterial-associated waste management.*

*Potential Applications of Nanotechnology in Agriculture: A Smart Tool for Sustainable Agriculture DOI: http://dx.doi.org/10.5772/intechopen.101142*

these wastes can be reduced, reused, and recycled effectively. Also, this new technique can be an asset for poor nations having poor sanitation, water scarcity, and inadequate resources [2, 158]. When crops are harvested, additional connected problems exist, such as crop waste, nearly 80% of the farm's biomass. The production of agricultural waste is hundreds of millions of tons annually [159]. Every year, a large amount of food and agricultural goods are wasted as agro-waste throughout the globe. It estimates that about one-third of the world's food produced for human use is lost or destroyed each year [160]. Minimizing agricultural product losses reduces resource pressures and therefore reduces the need for chemical fertilizers and pesticides [161]. It is thus time to manage waste strategically to recycle, recycle and reuse agro-purpose.

Nanotechnology is now confined to the energy, food hygiene, telecommunications, agriculture, and healthcare sectors and has now covered environmental protection and waste management. Green nanoparticles production is becoming more popular in a straightforward, ecologically friendly manner. The continual deposition of agricultural wastes or byproducts in nature has become a significant concern. Nanotechnology has the potential to be used in the reduction of waste generated during agricultural production. Agricultural wastes, including natural and non-natural wastes, may also be effectively used to produce nanoparticles.

#### **13. Conclusion and future perspectives**

Nanotechnology has a wonderful possibility in agriculture. Research on nanotechnology uses in agriculture is less than ten years old. However, given the growing inadequacy of traditional farming techniques and the excess capacity of the terrestrial ecosystem demands, we have little alternative but to investigate the nanotechnologies in all agricultural sectors. New technology is generally acknowledged as essential to the creation of national prosperity.

There's been a substantial improvement upon nanoparticles dependent programs in agriculture industries. Scanty reviews can be found about the suitable utilization as well as improvement associated with eco-friendly nanoparticles in several fields. Therefore, execution associated with nanomaterials may uplift the actual farming requirements and supply advantages in various methods. However, among the main constrict may be the toxicity associated with nanoparticles. Therefore, to conquer the actual poisonous results, various logical methods are now being created. One particular technique entails the utilization of (i) Natural organizations or even their items concerning manufacturing associated with nanoparticles that type among the eco-friendly procedures about functionality associated with nanoparticles. (ii) Bioconjugation as well as encapsulation associated with nanoparticles along with bioactive substances is guaranteeing area that prevents toxicity. (iii) Nanotechnology also offers options about degrading continual chemical substances into safe as well as occasionally helpful elements. (iv) Nanotechnology may effort to supply as well as essentially improve the actual systems presently utilized in environment recognition, realizing as well as remediation. (v) To be able to obtain prosperous utilization as well as commercialization associated with nanomaterials, various knowledge ought to work with others to style biomimetic nanomaterials as well as their assessment within the agriculture field.

In conjunction with information on the agriculture production system, nanotechnology demands a solid understanding of science as well as of production and material technologies. The severity of this task can draw talented brains into a career for agriculture. To succeed in this sector, human resources require advanced training, which is urgently necessary for new instruction programs, particularly at the graduation level.
