Fabricating Novel Nanoproducts for Their Use as Fertilizer

Fertilizer resources, especially phosphates and potassium are fast getting depleted. They also have poor use efficiency, burden farm economy, and pollute entire ecosystem. It was, therefore aimed to develop novel process and materials using nanotechnology. Novel process (patents applied) of nanofabrication and beneficiation of Rock Phosphate ore led to heavy-metal free phosphate-rich minerals and Zn-products. Novel P and Zn nanoproducts (patents applied) ensured supply of nutrients in plant available forms, and in conformity to environmental quality.


Introduction
Fertilizer use to supplement nutrient requirement of plants is steadily rising ever since its utility was demonstrated by Justus von Liebig in 1847.However, global fertilizer consumption during 1950-2013 has grown at alarming pace, but return of crop yield per unit of fertilizer-use in world's major agricultural countries has been steadily falling [1].The situation is further aggravated because phosphorus and potassium containing fertilizer resources are increasingly becoming scarce [2] threatening global food and nutrition security.
Existing fertilizers are known to cause soil acidity, damage soil carbon profile, harm beneficial micro-flora, weather clay minerals [3], and accumulate heavy metals (e.g., P fertilizers [4]).Another key problems of existing fertilizer materials are that most of them are salts consisting of one component of plantnutrient ion(s), while counter component is not very useful or, toxic (e.g., muriate of potassium that contains Cl - [5]).They thereby make irreparable damage to soils and food-quality, and as a consequence detrimental to human health.Such scenario calls for systemic fabrication of materials in such manner that they supply plant-nutrient ions in plant-available forms and comply with environmental quality for which nanotechnology is indispensable [6].

Nanofabrication process
Developing a nanofabrication process that would be simple, energy efficient and do not burden toxic load on environment is prerequisite to manufacture novel nanomaterials for their use as fertilizer and beyond it.Current industryfocused processes of nanofabrications or manufacturing nanoproducts involve physical and chemical vapour deposition, laser ablation, arc discharge, lithography for nano-deposition or nano-machining of atoms, molecules, compounds or ) due to presence of water in soil environment.All three forms are available to plants, and the release of phosphate ion will be through diffusion process.Advantage of the nanoproducts over conventional fertilizers is that in the nanoproducts P is readily available, and does not contain heavy metals and other contaminants.As the P resources are likely to be depleted in a few decades and costs of environmental clean-up from eutrophication is escalating, there is no escape route, but to stop agronomic practices of applying P fertilizers in amounts ~20-80 times than plant can remove.The present nanoproduct therefore, is likely to be a viable alternative to sustain agricultural production.The nanoproducts were characterized by Fourier Transformed Infra-red Spectroscopy, Scanning Electron Microscopy (SEM) and SEM-Energy Dispersion Spectroscopy, and Transmission Electron Microscopy.

Nano-zinc
Zinc (Zn) deficiency is wide spread in soils of the world, and it is acute in the fifty percent arable soils in India.Conventional zinc fertilizers do not adequately respond to the demands of plants over time and space.Four advanced Zn nano-materials were developed using kaolin and smectite clayminerals as receptacles.Subsequently, they were embedded into a polymer matrix.The products contained zinc in plant available forms (Zn 2+ ), and were suitable for soil application.The nanoproducts were characterized by: (i) basal spacing on intercalation of [Zn 6 (OH 2 ) 12 ] 12+ by X-ray Diffraction, (ii) identification of structural groups by Fourier Transformed Infra-red Spectroscopy, (iii) morphology by the Scanning Electron Microscopy (SEM), (iv) elemental composition by the SEM-Energy Dispersion Spectroscopy (SEM-EDS), and (v) size of nanoproducts by the Transmission Electron Microscopy.

Conclusion
Many existing commercial fertilizer materials have poor use efficiency and unwanted pollutants or counterparts in salts causing environmental load and detrimental to human health.Therefore they must be replaced by the novel materials -preferably in nanoform -that hold and release plantavailable forms of nutrients.These objectives were attained by inventing nanofabricating process in accordance to farming requirements and segregating heavy metal free P-containing minerals from Rock Phosphate ore, and by inventing P and Zn containing nano-products in clay mineral receptacles so that they are biosafe.

Fabricating Novel Nanoproducts for Their Use as Fertilizer Mukhopadhyay.
The final product was dried and stored in sterilized container.If the nanoproduct is applied to soil as fertilizer, it would release either phosphate ions (PO 4