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Title: Novel slow release nanocomposite nitrogen fertilizers: the impact of polymers on nanocomposite properties and function

Author
item PEREIRA, ELAINE - Embrapa
item DA CRUZ, CAMILA C.T. - Embrapa
item SOLOMON, AARON - University Of Maryland
item Cavigelli, Michel
item Le, Anh
item RIBEIRO, CAUE - Embrapa

Submitted to: Industrial and Engineering Chemistry Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/20/2015
Publication Date: 3/20/2015
Citation: Pereira, E.I., Da Cruz, C., Solomon, A., Cavigelli, M.A., Le, A.N., Ribeiro, C. 2015. Novel slow release nanocomposite nitrogen fertilizers: the impact of polymers on nanocomposite properties and function. Industrial and Engineering Chemistry Research. 54:3717-3725.

Interpretive Summary: While nitrogen fertilizers are essential to modern agriculture, their inherent properties result in substantial losses from agricultural fields. These losses represent substantial economic costs for farmers while contributing significantly to a number of pressing environmental concerns, including eutrophication of surface waters and global warming via the production of nitrous oxide, a powerful greenhouse gas and catalyst of stratospheric ozone. One means of increasing the amount of nitrogen fertilizers retained within a farm is to slow the release of mobile forms of nitrogen in the fertilizer material. This research reports on the impacts of combining a common nitrogen fertilizer, urea, with a common clay material, montmorillonite, and various concentrations of two different polymers, polyacrylamide hydrogel (HG) and polycaprolactone. The manufacturing process is simple and can be scaled up, allowing production of slow release fertilizers for relatively low cost. The polymers favorably impacted physical properties of the fertilizer materials and slowed release of urea in water. In a field experiment nitrous oxide emissions were reduced by more than 50% compared to emissions when the same amount of urea was as fertilizer to a winter wheat crop. This information will be of interest to fertilizer manufacturers, farmers, other scientists and policymakers interested in increasing nitrogen use efficiency.

Technical Abstract: Efficient use of fertilizers, especially nitrogen, is essential and strategic to agricultural production. Among the technologies that can contribute to efficient use of fertilizers are slow or controlled release products. This paper describes the impact on structure, urea release rate and function in the field of urea nanocomposites associated with an exfoliated clay mineral prepared using various concentrations of hydrophilic or hydrophobic polymers. The nanocomposites have a high nutrient load (75% by weight), which itself acts as a structural matrix. Our manufacturing process - the extrusion of a plastic mixture - is simple and can be scaled up, allowing granule production without high costs. Nanocomposites were prepared adding varying amounts (less than 4% by weight) of polyacrylamide hydrogel or polycaprolactone, which influenced mechanical properties and urea release profiles. Nitrous oxide (N2O) emissions in the field were reduced substantially for nanocomposites, whether comprised of polyacrylamide hydrogel or polycaprolactone.