**5. Biological mechanisms of nanofertilizers action**

Nanofertilizers have been advocated owing to higher NUE as plants cell walls have small pore sizes (up to 20 nm) which result in higher nutrient uptake [14]. Plant roots which act as the gateways for nutrients, have been reported to be significantly porous to nanomaterials compared to conventional manuring materials. The uptake of nanofertilizers can be improved by utilizing root exudates and molecular transporters through the ionic channels and creation of new micro-pores [15]. Nano-pores and stomatal openings in leaves have also been reported to felicitate nanomaterials uptake and their penetration deep inside leaves. It was concluded that in broad/faba bean (*Vicia faba*), nano-sized particles (43 nm) were instrumental in penetrating deep to leaf interior in large number compared to larger particles of more than 1.0 micrometer size [16]. Similarly, the leaf stomatal radii of Arabian coffee (*C. arabica*) was below 2.5 nm, while that of sour cherry (*P. cerasus*) were also below 100 nm [17] and thus effectiveness of nanofertilizers in enhancing nutrient uptake was suggested.

Nanofertilizers have also been supported to have higher NUE owing to higher transport and delivery of nutrients through plasmodesmata which are nanosized (50–60 nm) channels for transportation of ions between cells [18]. Carbon nanotubes transported fluorescent dyes to tobacco cells through enhanced penetration of cell membranes and effectively played the role of molecular transporters [19]. The nanoparticles of silica were also instrumental in transporting and delivering different cargoes to target sites in different plants [20].

**297**

depicted in **Table 1**.

*Nano-Fertilizers for Sustainable Crop Production under Changing Climate: A Global Perspective*

Mineral nutrients if applied to crops in the form of nanofertilizers hold potential to offer numerous benefits for making the crop production more sustainable and

1.Nanofertilizers feed the crop plants gradually in a controlled manner in contradiction to rapid and spontaneous release of nutrients from chemical fertilizers.

2.Nanofertilizers are more efficacious in terms of nutrients absorption and utilization owing to considerably lesser losses in the form of leaching and

3.Nanoparticles record significantly higher uptake owing to free passage from nano sized pores and by molecular transporters as well as root exudates. Nanoparticles also utilize various ion channels which lead to higher nutrient uptake by crop plants. Within the plant, nanoparticles may pass through plasmodesmata that results in effective delivery on nutrient to sink sites.

4.Due to considerably small losses of nanofertilizers, these can be applied in smaller amounts in comparison to synthetic fertilizers which are being applied in greater quantities keeping in view their major chunk that gets lost owing to

5.Nanofertilizers offer the biggest benefit in terms of small losses which lead to

6.Comparatively higher solubility and diffusion impart superiority to nanoferti-

7.Smart nanofertilizers such as polymer coated fertilizers avoid premature contact with soil and water owing to thin coating encapsulation of nanoparticles such as leading to negligible loss of nutrients. On the other hand, these become available as soon as plants are in position to internalize the released nutrients.

**7. Field evidences of nanofertilizers use for sustainable crops production**

The research findings of a field investigation proved in line with the postulated hypothesis where nano nitrogen fertilizers proved instrumental in boosting the productivity of rice. It was inferred that nano nitrogen fertilizer hold potential to be used in place of mineral urea and it can also reduce environmental pollution caused by leaching, de-nitrification and volatilization of chemical fertilizers [22]. Similarly, exogenously applied nutrients as nanomaterials increased the vegetative growth of cereals including barley [23] (man), while in contrast, nanofertilizers applied in conjunction with reduced doses of mineral fertilizers were found to be instrumental in boosting yield attributes and grain yield of cereals [24]. Nanofertilizer of zinc applied as ZnO was found to be instrumental in boosting peanut yield due to robust plant growth, increased chlorophyll content of leaves and significantly better root growth [25]. The growth and yield boosting impact of different nanomaterials is

**6. Nanofertilizers advantages over conventional mineral fertilizers**

*DOI: http://dx.doi.org/10.5772/intechopen.89089*

volatilization.

leaching and emission.

lower risk of environmental pollution.

lizers over conventional synthetic fertilizers.

eco-friendly [21]. Some of salient advantages are;

*Nano-Fertilizers for Sustainable Crop Production under Changing Climate: A Global Perspective DOI: http://dx.doi.org/10.5772/intechopen.89089*
