Search

Urea cocrystal materials are a potential fertilizer source that has shown to decrease environmental nitrogen losses. Novel nitrogen (N)-containing urea cocrystal fertilizers, CaSO4·4urea (UC1) and Ca(H2PO4)2·4urea (UC2), were synthesized using the mechanochemical method to form stable urea cocrystals to be tested as a fertilizer source for turfgrass. The objectives of this study were to 1) evaluate the response of ‘Tifway’ hybrid bermudagrass (Cynodon dactylon × C. traansvalensis Burt Davy) to N fertilization by urea cocrystals and traditional coated urea products (MU·PCU, methylene urea, urea, polymer-coated urea; PCU, polymer-coated urea, urea) supplied at two rates at the beginning of two, 10-week study periods conducted under a greenhouse setting and 2) investigate N release behavior of urea and two cocrystal products using a rapid water release test. In the turfgrass response study conducted in the greenhouse, improved turfgrass quality above the minimum quality threshold was observed when averaging across all products. For normalized difference vegetation index (NDVI), cocrystal outperformed all other products in the summer study and both cocrystal products outperformed the traditional product (MU·PCU) in the winter study. Further, both cocrystal products showed favorable growth responses compared with the commercial products provided by positive clipping production and vertical extension rates. In the nitrogen release experiment, a rapid water release test revealed the N release peak of urea was significantly higher than both UC1 and UC2. Furthermore, significantly higher N was leached from urea (15% loss) compared with both UC1 and UC2 (≈8% loss). Results from both studies provide evidence supporting suitability of urea cocrystal application on bermudagrass and potential as a slow-release fertilizer source through sustained turfgrass vigor, growth, decreased N release peak, and decreased leaching losses.

This article presents the results of optimizing microalgae Chlorella sp. cultivation to obtain a higher amount of biomass and to use cheaper suitable waste for algae cultivation. It has been found that the most suitable waste for growing microalgae is landfill leachate, which can replace the source of nitrogen in the cultivation medium. The largest concentration of microalgae Chlorella sp. biomass is obtained in the medium containing 0.08 g·L−1 nitrogen acquired from the landfill leachate. For fertilizer production, the microalgae biomass suspension was centrifuged and analyzed. The chemical composition of microalgae biomass was found to be sufficiently good to produce granular nitrogen fertilizer with bioactive materials because it contains primary nutrients (3.49% nitrogen, 2.10% phosphorus, and 0.50% potassium) along with secondary nutrients (13.42% calcium and 3.69% magnesium) and 75.33% organic matter and trace elements. Also, microalgae biomass does not contain any heavy metals. The use of a microalgae suspension allows to reduce the amount of moisture used in the production of fertilizers. If optimal conditions are chosen, it is possible to granulate bioactive nitrogen fertilizer that satisfies all the criteria.