Nanoclay polymer composites loaded with urea and nitrification inhibitors for controlling nitrification in soil

ABSTRACT

Nanoclay polymer composites (NCPCs) were synthesized with partially neutralized acrylic acid and bentonites and loaded with urea and nitrification inhibitors (NIs) to act as a slow release carrier of nitrogen (N). The resulting product was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The XRD of NCPCs revealed that the bentonite layers were completely exfoliated and dispersed in the composite after the polymerization. The water absorbency of pure polymer (Acrylic acid + Acrylamide) was 197.53 g g⁻¹ and 137.75 g g⁻¹ by nanocomposite (8% nanobentonite) in distilled water. The nitrification inhibition ability of these NCPCs was evaluated by incubation study for 60 days in laboratory at 28°C and 50% water-holding capacity. The Schiff base -NCPCs were most effective at inhibiting nitrification (30–87%) compared to dicyandiamide and Neem oil. A column study was performed to know the movement of NH₄-N and NO₃-N at three different depths. Result showed that the Schiff base -NCPC decreased nitrate movement by 78.5% at the depth of 5 cm in soil column. The slow release of nitrogen and good water retention capacity confirmed that these NCPCs can be viably exploited for application in agriculture.

KEYWORDS:

• Urea
• nitrification inhibitor
• nanoclay polymer composite
• soil nitrate leaching

Acknowledgments

The authors thank the Head, Division of Soil Science and Agricultural Chemistry, ICAR-Indian Agricultural Research Institute, New Delhi, India for providing all the required facilities to carry out the present investigation.

Disclosure statement

No potential conflict of interest was reported by the authors.