Background Nano-fertilizers, which contain nanoparticles (NPs), are increasingly recognized for their potential to improve crop yields and decreasing reliance on traditional nitrogen-, phosphorus-, and potassium (NPK)-based chemical fertilizers. Traditional NPK fertilizers often suffer from poor nutrient solubility in soil water, causing suboptimal nutrient uptake. As such, the current work used the central composite design from response surface method (CCD-RSM) to produce an optimized slow-release ZnO NPs/PVA/Alg hydrogel nano-fertilizer comprising zinc oxide NPs (ZnO NPs) and polyvinyl alcohol/alginate (PVA/Alg). Methodology Three key input factors, which are the concentration of ZnO NPs (X1 = 20,60,100 ppm), the amount of Alg (X2 = 0.1,0.55,1.0 g), and the amount of PVA (X3 = 0.1,0.55,1.0 g), were used to investigate the output responses, which were the hydrogel nano-fertilizers yield (Y1), concentration of zinc ions (Zn2+) released over 24 h (Y2), and swelling ratio (α) (Y3). Several characterization tools such as field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) mapping, and X-ray diffraction (XRD) were used to confirm the intrinsic characteristics of the optimized ZnO NPs/PVA/Alg hydrogel nano-fertilizers. The disc diffusion method was then used to conduct an antibacterial study of the hydrogels, while the efficiency of hydrogel was observed on the number of leaves and height of water spinach (Ipomoea aquatica) and mung bean (Vigna radiata L.) plants. Results The optimal synthesis parameters were at X1 = 20 ppm, X2 = 1.0 g, and X3 = 0.891 g, which produced Y1 = 31.97 g, Y2 = 0.025 mg/L, and Y3 = 0.23. The optimized ZnO NPs/PVA/Alg hydrogel was found to have an amorphous folded morphology that helps it retain water. The antibacterial study revealed that the optimized ZnO NPs/PVA/Alg hydrogel nano-fertilizers had zones of inhibition (ZOI) measuring 24 and 29 mm against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), respectively, which were better than ZnO NPs and PVA/Alg. This pronounced antibacterial activity highlights the hydrogel's potential for agricultural pathogen control, particularly concerning potential collateral effects on non-target, beneficial soil microorganisms. Lastly, the heights of water spinach and mung bean plants post-application using the ZnO NPs/PVA/Alg hydrogel nano-fertilizers were 21.0 cm and 26.9 cm, respectively. This was almost similar to the plants grown using traditional NPK fertilizers. Conclusion Therefore, these slow-release hydrogel nano-fertilizers are not only environmentally friendly with use of well-known biodegradable and biocompatible compounds such as ZnO NPs/PVA/Alg, but they also own excellent antibacterial properties and yield comparable plant growth to traditional NPK fertilizers. Nevertheless, future studies may examine using different types of metal oxide NPs, soil moisture levels, and pH conditions to synthesize hydrogel nano-fertilizers.

Optimization of beads polyvinyl alcohol/alginate hydrogel nano-fertilizers incorporated zinc oxide nanoparticles for sustainable plant growth

期刊论文
发表日期：

2026年7月7日

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Nur Syafiqah Farhanah Dzulkharnien,
Rasul Sauket Ali,
Rosiah Rohani,
Peer Mohamed,
Alya Athirah Mohd Idris

摘要

Background

Nano-fertilizers, which contain nanoparticles (NPs), are increasingly recognized for their potential to improve crop yields and decreasing reliance on traditional nitrogen-, phosphorus-, and potassium (NPK)-based chemical fertilizers. Traditional NPK fertilizers often suffer from poor nutrient solubility in soil water, causing suboptimal nutrient uptake. As such, the current work used the central composite design from response surface method (CCD-RSM) to produce an optimized slow-release ZnO NPs/PVA/Alg hydrogel nano-fertilizer comprising zinc oxide NPs (ZnO NPs) and polyvinyl alcohol/alginate (PVA/Alg).

Methodology

Three key input factors, which are the concentration of ZnO NPs (X₁ = 20,60,100 ppm), the amount of Alg (X₂ = 0.1,0.55,1.0 g), and the amount of PVA (X₃ = 0.1,0.55,1.0 g), were used to investigate the output responses, which were the hydrogel nano-fertilizers yield (Y₁), concentration of zinc ions (Zn²⁺) released over 24 h (Y₂), and swelling ratio (α) (Y₃). Several characterization tools such as field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) mapping, and X-ray diffraction (XRD) were used to confirm the intrinsic characteristics of the optimized ZnO NPs/PVA/Alg hydrogel nano-fertilizers. The disc diffusion method was then used to conduct an antibacterial study of the hydrogels, while the efficiency of hydrogel was observed on the number of leaves and height of water spinach (Ipomoea aquatica) and mung bean (Vigna radiata L.) plants.

Results

The optimal synthesis parameters were at X₁ = 20 ppm, X₂ = 1.0 g, and X₃ = 0.891 g, which produced Y₁ = 31.97 g, Y₂ = 0.025 mg/L, and Y₃ = 0.23. The optimized ZnO NPs/PVA/Alg hydrogel was found to have an amorphous folded morphology that helps it retain water. The antibacterial study revealed that the optimized ZnO NPs/PVA/Alg hydrogel nano-fertilizers had zones of inhibition (ZOI) measuring 24 and 29 mm against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), respectively, which were better than ZnO NPs and PVA/Alg. This pronounced antibacterial activity highlights the hydrogel's potential for agricultural pathogen control, particularly concerning potential collateral effects on non-target, beneficial soil microorganisms. Lastly, the heights of water spinach and mung bean plants post-application using the ZnO NPs/PVA/Alg hydrogel nano-fertilizers were 21.0 cm and 26.9 cm, respectively. This was almost similar to the plants grown using traditional NPK fertilizers.

Conclusion

Therefore, these slow-release hydrogel nano-fertilizers are not only environmentally friendly with use of well-known biodegradable and biocompatible compounds such as ZnO NPs/PVA/Alg, but they also own excellent antibacterial properties and yield comparable plant growth to traditional NPK fertilizers. Nevertheless, future studies may examine using different types of metal oxide NPs, soil moisture levels, and pH conditions to synthesize hydrogel nano-fertilizers.