A controlled-release fertilizer (CRF) is a granulated fertilizer that releases nutrients gradually into the soil. Slowing the release of plant nutrients from fertilizers can be achieved by different methods and the resulting products are known as slow-or controlled-release fertilizers. The gradualness of the release is determined by the low solubility of the chemical compounds in the soil moisture.
Nanotechnology encompasses a range of technologies related to the manipulation of matter at the length scale of 1-100 nm. Agriculture today is faced with demands for greater efficiency in food production due to a growing population and a shrinking arable land base and water resources. The integration of nanotechnology in fertilizer products will improve release profiles and increase uptake efficiency, leading to significant economic and environmental benefits.
With controlled release fertilizers, the principal method is to cover a conventional soluble fertilizer with a protective coating (encapsulation) of a water-insoluble, semi-permeable or impermeable-with pores material. Slow-release fertilizers (various forms including fertilizer spikes, tabs, etc.) reduce the problem of "burning" the plants due to excess nitrogen. Polymer coating of fertilizer ingredients gives a 'true time-release' or 'staged nutrient release' (SNR) of fertilizer nutrients.
Release mechanism of CRF
