Enhanced efficiency fertilisers: a review of formulation and nutrient release patterns

Abstract

Fertilisers are one of the most important elements of modern agriculture. The application of fertilisers in agricultural practices has markedly increased the production of food, feed, fuel, fibre and other plant products. However, a significant portion of nutrients applied in the field is not taken up by plants and is lost through leaching, volatilisation, nitrification, or other means. Such a loss increases the cost of fertiliser and severely pollutes the environment. To alleviate these problems, enhanced efficiency fertilisers (EEFs) are produced and used in the form of controlled release fertilisers and nitrification/urease inhibitors. The application of biopolymers for coating in EEFs, tailoring the release pattern of nutrients to closely match the growth requirement of plants and development of realistic models to predict the release pattern of common nutrients have been the foci of fertiliser research. In this context, this paper intends to review relevant aspects of new developments in fertiliser production and use, agronomic, economic and environmental drives for enhanced efficiency fertilisers and their formulation process and the nutrient release behaviour. Application of biopolymers and complex coacervation technique for nutrient encapsulation is also explored as a promising technology to produce EEFs.

Nitrogen loss by volatilization of nitrogen fertilizers applied to coffee orchard

“…Moreover, sulfur-coated urea has been commercialized both alone and in the form of blends/mixtures. The urease inhibitors added to urea result in extra costs of approximately 15 -30% (Azeem, 2014;Timilsena et al, 2015). Table 3: Values of pH in water at 0-5 cm soil layer and N-NH 3 loss (%) from conventional urea, ammonium nitrate, urea + 0.15 % Cu + 0.4% B, urea + anionic polymers, urea + S 0 + polymers and urea + plastic resin in the dose of 150 kg ha -1 (Average of three fertilizations).…”

Fortification of micronutrients for efficient agronomic production: a review

“…Nanoencapsulation of micronutrients is a research area where knowledge gaps still exist, for although the ability of crops to take up nano and micron-size polymers loaded with drugs have been demonstrated (e.g., Zhang et al 2012), the uptake of such polymers when loaded with nutrients, as well as the potential for release of the encapsulated nutrients inside the plant cell, is yet to be understood. In this regard, lessons could be learned from two facts (i) that bare metallic nutrient NPs are taken up and (ii) that polymer technology is at the core of controlled-release fertilizers (Timilsena et al 2015). Hence, nanopolymers could be engineered to timely dissolve in the rhizosphere, releasing the encapsulated nutrients in sync with the plant's need (Monreal et al 2015;Timilsena et al 2015).…”

“…In this regard, lessons could be learned from two facts (i) that bare metallic nutrient NPs are taken up and (ii) that polymer technology is at the core of controlled-release fertilizers (Timilsena et al 2015). Hence, nanopolymers could be engineered to timely dissolve in the rhizosphere, releasing the encapsulated nutrients in sync with the plant's need (Monreal et al 2015;Timilsena et al 2015). Recently, Monreal et al (2015) proposed the integration into nanopolymer technology for micronutrient fertilizers of biosensors that are based on, and therefore respond to, specific nutrient-solubilizing root exudate signals.…”

Nitrous oxide emission and fertiliser nitrogen efficiency in a tropical sugarcane cropping system applied with different formulations of urea

“…Of the slow-release techniques, polymercoating is relatively new and does not cause a substantial reduction in N content of the product. Polymer-coated fertiliser relies on a physical barrier around the fertiliser prills to control the release of N to the surrounding soil, with the potential to better match crop N demand (Timilsena et al 2014). The release rate can be manipulated by changing characteristics of the coating, including polymer type and thickness.…”