Much of the fertilizers are unavailable to plants as
they are lost as run-off causing pollution. Localized application of large
amount of fertilizer, in the form of ammonium salts, urea and nitrate or
phosphate compounds are harmful. Nanomaterials have potential contribution in
slow release of fertilizers. Fertilizers with sulphur nanocoatings are useful
slow release fertilizers. In addition to sulphur nanocoatings or encapsulation
of urea and phosphate and their release will be beneficial to meet the soil and
crop demands. Other nanomaterials with potential applications include kanolin
and polymeric biocompatible NPs. We can use biodegradable,
polymeric chitosan NPs for controlled release of the NPK fertilizer sources
such as urea, calcium phosphate and potassium chloride. Biofertilizers are live formulations of beneficial
microorganism such as the fungal mycorrhizae, plant growth promoting
rhizobacteria Rhizobium, Azotobacter, Azosprillum and blue green algae,
phosphate solubilizing bacterial Pseudomonas
sp and Bacillus sp. Some
constraints in their widespread usage are short shelf life, lack of suitable carrier
materials, susceptibility to high temperature, problems in transportation and
storage. Potential application of
polymeric NPs are for coating of biofertilzer preparations to yield
formulations that are resistant to desiccation. Micronutrients promote optimum
plant growth. Supplementation of soil with micronutrients trapped in NMs for
their slow release would promote plant growth and soil health.
