Production of Urea/Acetylated-ligninsulfonate Matrix as SRFs and Investigation the Effect of Hydrodynamic Conditions on the Release Rate Using Biot Number

Background: This study aimed to investigate the effect of the hydrodynamic condition on the release rate of urea/acetylated lignin sulfonate (Ac-LS) matrix as slow-release fertilizers (SRFs). Therefore, two models were developed using the mass transfer balance for the finite/infinite volume of fluids, solving finite integral transform/separation of a variable. In these models, the Biot number that verified the hydrodynamic condition appeared. Methods: In the experimental section, the urea/Ac-LS matrix fertilizer was produced. The morphological, thermal, chemical, and mechanical properties of the LS, Ac-LS, urea, and urea/Ac-LS matrix were analyzed using Fe-SEM, TGA, XRD, and SANTAM. Finally, the nitrogen release of the matrix fertilizer was investigated at 25°C for different impeller speeds. Results: The results showed that the thermal and mechanical resistance of urea/Ac-LS, with strong interaction, increased rather than pure urea or Ac-LS. The models were also validated using experimental data. The results further showed that in both states, the external resistance of the mass transfer decreased with increasing impeller speed, and the nitrogen release rate increased with increasing Biot number. Conclusion: It was also observed that, in a given hydrodynamic condition, initially, the release rate in the finite environment was less than the infinite; however, after a while, the type of environment did not affect the release rate

Release of Nitrogen from Granulate Mineral and Organic Fertilizers and Its Effect on Selected Chemical Parameters of Soil

The objective of this work was the evaluation of the release patterns of nitrogen from various types of fertilizers and their impact on selected chemical parameters of calcareous soil. Three mineral fertilizers and two organic fertilizers were tested in the laboratory for 35 days. This study showed the rapid release of nitrogen from mineral types. More than 70% of the nitrogen was released from the ammonium granules and 98% from the urea granules. The rate of nitrogen release from pellets of organic origin was much slower than from mineral pellets, the released N was 15–28% of the original amount. Soil pH was altered by incubation. The content of soil N changed significantly due to the incubation of N mineral fertilizers; no changes were observed for organic fertilizers. The EC value of the soil solution was significantly modified under the influence of mineral granules, it reached a maximum of 1147 µS cm−1 on the 10th day, and for organic fertilizers of 944 µS cm−1 on the 35th day. The results of this study characterize each N release pattern, providing data to support a more efficient nutrient management strategy in calcareous soils and the effect of incubated fertilizers on soil chemical parameters.

Calorimetry, physicochemical characteristics and nitrogen release from extruded urea

Our hypothesis was that extrusion of urea associated with corn may reduce N solubilization and increase the nutritional quality of this food for ruminants. We aimed to physically and chemically characterize a corn and urea mixture before and after the extrusion process. It was evaluated morphological differences by scanning electron microscopy, nitrogen solubilization, and compound mass loss by thermogravimetry. In scanning electron microscopy, extruded urea showed agglomerated and defined structures, with changes in the morphology of starch granules and urea crystals, differing from the arrangement of the corn and urea mixture. The extruded urea maintained a constant nitrogen release pattern for up to 360 min. In thermogravimetry, extruded urea presented a higher temperature to initiate mass loss, that is, the disappearance of the material with increasing temperature, but the mass loss was lower when compared to the first event of the corn and urea mixture. In conclusion the process of extrusion of urea with corn modifies the original structures of these ingredients and controls the release of nitrogen from the urea, maintaining in its formation an energy source optimizing the use of nitrogen by ruminal bacteria, because the more synchronized the release of starch (energy) and nitrogen, the better the use by ruminal microorganisms.

Effect of urea modified hydroxyapatite nano fertilizer on nitrogen release pattern in red soil

A laboratory incubation study was conducted during 2018 at College of Agriculture V.C. Farm, Mandya using CRD design with eight treatments and three replication. Treatments included were T1:100% Nitrogen-Urea (NU), T2 to T4: NU: UHA @ 75:25, 50:50 and 25:75 per cent, respectively and T5 to T7: UHA @ 50, 75 and 100%, respectively, T8: Absolute control. Results revealed that application of 100 per cent N through nano UHA increased the content of ammonical-N at 5 DAI (653.3 μg g-1) but the content decreased at 10 DAI (583.3 μg g-1) and increased to 716.7 μg g-1 at 15 DAI and maintained it upto 20 DAI while, it decreased at 45 DAI. The nitrate –N release was highest (596.7 μg g-1) at 10 DAI in T7 treatment and maintained it upto 20 DAI and decreased at 45 DAI. Similar pattern was observed with the application of 75 and 50 per cent N-UHA treatments (T6 and T5, respectively). The amount of release of ammonical and nitrate N was proportional to the amount N added through UHA at any sampling interval.