Smart Fertilizer Research Articles

Controlled Release of Phosphate from Layered Double Hydroxide Structures: Dynamics in Soil and Application as Smart Fertilizer

A route is proposed to produce a hydrotalcite-like layered double hydroxide structure ([Mg-Al]-LDH) for phosphate fertilization. The mechanism of controlled phosphate release from the structure was investigated. The preparation strategy resulted in a phosphorus content of around 40 mg·g–1 LDH, which was higher than previously reported for related fertilizers. The release of phosphate into water from [Mg-Al-PO4]-LDH continued over a 10-fold longer period, compared to release from KH2PO4. Analysis using 31P NMR elucidated the nature of the interactions of phosphate with the LDH matrix. In soil experiments, the main interaction of P was with Fe3+, while the Al3+ content of LDH had no effect on immobilization of the nutrient. Assays of wheat (Triticum aestivum) growth showed that [Mg-Al-PO4]-LDH was able to provide the same level of phosphate nutrition as other typical sources during short periods, while maintaining higher availability of phosphate over longer periods. These characteristics confirmed the potential of this preparation route for producing controlled release fertilizers, and also revealed fundamental aspects concerning the interactions of phosphate within these structures.

A Novel, Simple Route to Produce Urea:Urea–Formaldehyde Composites for Controlled Release of Fertilizers

Nitrogen loss through NH3 volatilization is a primary concern for urea as fertilizer due its fast hydrolysis by soil urease. To minimize this problem herein we developed a partially-polymerized urea–formaldehyde granule as a slow-release fertilizer, by melt stage process as a viable route for large-scale production. In this product the unreacted urea fraction acts as a fast release nutrient source while the polymerized fraction acts in longer times depending on the polymerization degree. This characteristic was analyzed by means of soil incubation experiments (up to 42 days), where the available NH4 + contents along time indicated significant lower N losses compared to conventional fertilizer, even for low-polymerized materials. Residual N in the structure was kept stored in the soil for future use by plants, as desired in many agricultural practices, showing that this simple polymerization method provides a smart fertilizer controlled by chemical structure.

Smart fertilizers: preparation and characterization of gelatin-based hydrogels for controlled release of MAP and AN fertilizers

Purchase online the PDF of Smart fertilizers : preparation and characterization of gelatin-based hydrogels for controlled release of MAP and AN fertilizers, Pulat, M.,Yoltay, N. - Pisa University Press - Article

Multifunctional Environmental Smart Fertilizer Based on l-Aspartic Acid for Sustained Nutrient Release.

Fertilizer is one of the most important elements of modern agriculture. However, conventional fertilizer, when applied to crops, is vulnerable to losses through volatilization, leaching, nitrification, or other means. Such a loss limits crop yields and pollutes the environment. In an effort to enhance nutrient use efficiency and reduce environmental pollution, an environmental smart fertilizer was reported in the current study. Poly(aspartic acid) and a degradable macro-cross-linker based on l-aspartic acid were synthesized and introduced into the fertilizer as a superabsorbent to improve the fertilizer degradability and soil moisture-retention capacity. Sustained release behavior of the fertilizer was achieved in soil. Cumulative release of nitrogen and phosphorus was 79.8% and 64.4% after 30 days, respectively. The water-holding and water-retention capacities of soil with the superabsorbent are obviously higher than those of the control soil without superabsorbent. For the sample of 200 g of soil with 1.5 g of superabsorbent, the water-holding capacity is 81.8%, and the water-retention capacity remains 22.6% after 23 days. All of the current results in this study indicated that the as-prepared fertilizer has a promising application in sustainable modern agriculture.