| 【Objective】 The study was conducted to develop a slow-release fertilizer with multiple nutrients, excellent nitrogen slow-release performance, simple process, and semi-interpenetrating network structure.【Method】By using solution polymerization with in situ extrusion technology, the polymerization and processing processes were combined. With amino acid powder (AARP) and ferrous sulfate (FeSO4) as raw materials, AARP and AARPFe were compounded with urea-formaldehyde (UF) macromolecular chains to form slow-release fertilizers with semi-interpenetrating network structures (AARP-UF and AARPFe-UF). The structures of the slow-release fertilizers were characterized and analyzed by infrared spectroscopy, X-ray diffraction and thermogravimetry, and the surface morphology was observed by scanning electron microscopy (SEM). The compression strength and nitrogen nutrient release rate in still water and soil were measured to investigate the effects of adding AARP and AARPFe on the slow-release performance and to analyze the reasons for their performance improvement. 【Result】The crystallinity of the three slow-release fertilizers UF, AARP-UF, and AARPFe-UF were 67.9%, 59.2%, and 57.4%, respectively, and the compression strengths were 1.64, 3.01 and 4.06 MPa. The initial nitrogen release rates in still water were 24.8%, 18.6%, and 15.1% respectively, and the cumulative release rates in soil after 90-daytreatment were 55.9%, 51.4%, and 46.3%, respectively. The addition of AARP and AARPFe disrupted the crystal structure of UF molecular chains and formed hydrogen bonding interactions, which reduced the crystallinity of the slow-release fertilizer, increased the compression strength, and significantly improved the nitrogen slow-release performance. Combining all the results, the effect of slow-release fertilizer AARPFe-UF was optimal. 【Conclusion】The prepared new slow-release fertilizer solves the problem of the high initial nitrogen release rate of urea-formaldehyde fertilizer and avoids the waste of resources. The fertilizer prepared with green and environment-friendly raw materials shows excellent comprehensive performance, which is
conducive to industrial production. AARP contains natural nutrients that have ecological effects and contribute to sustainable development of agricultural systems. |
