**Abstract**

Since green revolution, chemical fertilizers are deemed an indispensable input of modern crop production systems, but these have associated environmental and ecological consequences. Loss of nutrients from agricultural fields in the form of leaching and gaseous emissions has been the leading cause of environmental pollution and climate change. Ensuring the sustainability of crop production necessitates exploring other sources of nutrients and modifying prevalent nutrient sources. Nanotechnology, which utilizes nanomaterials of less than 100 nm size, may offer an unprecedented opportunity to develop concentrated sources of plant nutrients having higher-absorption rate, utilization efficacy, and minimum losses. Nanofertilizers are being prepared by encapsulating plant nutrients into nanomaterials, employing thin coating of nanomaterials on plant nutrients, and delivering in the form of nano-sized emulsions. Nanopores and stomatal openings in plant leaves facilitate nanomaterial uptake and their penetration deep inside leaves leading to higher nutrient use efficiency (NUE). Nanofertilizers have higher transport and delivery of nutrients through plasmodesmata, which are nanosized (50–60 nm) channels between cells. The higher NUE and significantly lesser nutrient losses of nanofertilizers lead to higher productivity (6–17%) and nutritional quality of field crops. However, production and availability, their sufficient effective legislation, and associated risk management are the prime limiting factors in their general adoption as plant nutrient sources.

**Keywords:** controlled release fertilizers, eutrophication, nanogels, encapsulated nutrients, slow released fertilizers

### **1. Introduction**

Intensive farming practices introduced and evolved since the inception of green revolution have been deemed unsustainable as the utilization efficacy of applied chemicals including mineral fertilizers has remained below 30% [1]. Fertilizers have taken axial role with respect to boosting crops yield and nutritional quality especially after the development of fertilizer responsive crop varieties. Among mineral nutrients, nitrogen is the first and foremost nutrient

required for crop plants as it is the constituent of chlorophyll and many proteins and enzymes and thus plays a significant role during the vegetative growth of crops. Nitrogen is absorbed by the plants in the form of nitrate (NO<sup>−</sup> 3) and ammonium (NH<sup>+</sup> 4) [2]. Nitrogen is lost through the processes of nitrate leaching, de-nitrification and ammonia volatilization. Loss of mineral nutrients through leaching and runoff to surface and ground water along with abundant volatilization constitute growing concerns owing to economic losses and environmental pollution. Conventional application techniques are resulting in seriously overdosing of chemical fertilizers which has become evident through the phenomenon of eutrophication (algal growth on the surface of water bodies due to nutrients enriched water, which hampers oxygen supply to fish) in many European and North American countries. Moreover, nitrogen volatilization results in the release of nitrous oxides and thus being the greenhouse gases, contribute to the global warming. It is really unfortunate that modern profit-oriented farming systems encompass nitrogenous fertilizers use efficiency of only 45–50%, while the corresponding figure for phosphorous fertilizers has been reported to be only 10–25% [3].

It is also pertinent to mention that ammonium ions react with alkaline rain water which leads to the formation of ammonia gas that escapes into the atmosphere and thus becoming a source of environmental pollution. Whenever, there is excess of nitrogen, more and more nitrates and ammonium ions get accumulated in the leaves of crops especially leafy vegetables and become detrimental to human health. In addition, nitrate rich diets have been reported to be associated with numerous human diseases such as bladder and gastric cancer as well as methemoglobinemia [4]. It is being stressed to deliver the required quantities of active agents only where they are direly needed. Environmentalists and consumers call for reducing the use of synthetic fertilizers to decrease pollution and residue effect on form produces along with conserving agro-ecosystems.

Nanotechnology is a promising field of research which has the potential to offer sustainable remedies to pressing challenges confronted to modern intensive agriculture. Nanotechnology employs nanomaterials which typically have the size of 1–100 nm and this small size imparts unique characteristics and benefits to nanomaterials. In addition to numerous other benefits, large surface area offers opportunity for better and effective interaction of nanoparticles to target sites. Nanofertilizers hold potential to fulfill plant nutrition requirements along with imparting sustainability to crop production systems and that too without compromising the crops yield [5].

This chapter entails and attempts to fulfill the need to periodically compile and review the present state and advances on nanofertilizers and to spur interest for conducting further in-depth research. The ultimate goal is to synthesize and assess the role of nanofertilizers in boosting nutrients uptake and nutrients use efficiency, reducing losses through leaching and gaseous emissions along with reducing the risk of nutrient toxicity for ensuring food security achieved through higher productivity and economic turn outs by practicing the sustainable farming practices. This chapter briefly sheds light on the critical role of nanotechnology pertaining to modern farming practices, its potential in developing smart fertilizers, nanofertilizers and their different types of formulations, biological mechanism of nanofertilizers in plants, numerous advantages offered by nanofertilizers and field evidences of superior performances of nanoparticles in imparting critical characteristics to crop plants leading to higher productivity. Lastly, few limitations pertaining to the development and use of nanoparticles as plant nutrient source have also been described.

**295**

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

Nanotechnology encompasses controlling matter at 1–100 nm dimensions for utilization in taking images, measurements and preparing models for making virtual predictions along with manipulation of matter at nanoscale. Like all other fields, the solid impact of nanomaterials is also being felt in agriculture sector. Previously, nanoencapsulation entailing encapsulation of active agents by microspheres of starch on a matrix having nanopores proved its resilience in accurately delivering the active agents to target sites [6]. These nanocapsules or micro-beads become attached to heir of bees in the similar fashion to pollens and keep parasites at bay owing to slow release of active agents gradually and slowly. Thus, nanoencapsulation resulted in minimum use of active agents and offered the maximum protection to bees against parasites. On the similar fashion, nanogels were developed which assist in controlled release of pheromones from insects to offer them protection against diversified pests. Nanoencapsulation has also yielded encouraging results for improving the fertilizer

**2. Critical applications of nanomaterials in agriculture**

use efficacy with significant reduction of active ingredients use [7].

In order to detect pathogen and to prolong the shelf life of packaged foods, nanosensors and nanobiosensors have given encouraging results. However, development of nanomaterials using nanotechnology is an evolving field of research and future is destined to witness extensive and multidimensional benefits in food production and preservation. In future, it will be impossible to ensure food and nutritional security without developing nanomaterials based technologies for food

**3. Nanotechnology's strategic potential in developing fertilizers of** 

**4. Nanoscale fertilizers and their formulations**

Modern intensive farming systems utilize organic and mineral manures in order to supply essential plant nutrients, but this approach has resulted in serious deterioration of ecosystems and environment [8]. Loss of nitrogen as nitrous oxide and nitrates leaching has resulted in eutrophication and manifesting the impacts of global warming and climate change. Phosphate fertilizers have even lesser nutrient use efficacy (NUE) that has been reported to be below 20% [9]. Nanofertilizers have the potential to enhance NUE owing to higher nutrients uptake caused by smaller surface area of nanomaterials which increases nutrient-surface interaction. Along with boosting crops yield on sustainable basis, nanofertilizers hold potential to put a halt to environmental pollution caused by fertilizers. Slow release fertilizers (chemical compounds having slight solubility in water or other solvents and get broken down gradually and slowly by soil microbial population) coated with nanoparticles significantly reduced nitrate leaching and de-nitrification [10]. Moreover, controlled releasing fertilizers (have higher solubility in contrast to slow release fertilizers but are coated with materials which significantly reduce the exposure of active ingredient with the solvent resulting in controlled liberation of nutrients through diffusion) coated with nanomaterials for reducing surface area my provide excellent of source of supplying plant nutrients in times to come.

Different fertilizers inputs have been reported to be resized into smaller fractions through mechanical means or by employing specific chemical methods,

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

production and agriculture.

**future**

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