Fate of chemical constituents of prosopis leaves during the conversion of the leaves into an organic fertiliser

ABSTRACT

When the otherwise toxic and allelopathic leaves of prosopis (Prosopis juliflora) are vermicomposted, the end product becomes a benign organic fertiliser. This paper describes extensive analytical studies, based on Fourier transform infrared spectroscopy, thermal analysis, and gas chromatographic-mass spectroscopic analysis, carried out to identify the change in the chemical composition of prosopis leaves that occur as the leaves go through biodegradation. All the studies indicate that a transformative change is seen to occur, leading to the breakdown of allelochemicals and other toxic ingredients into simpler molecules that are not known to be toxic. There is also a major shift in the arrangement of the molecules. Vermicompost derived from six different species of earthworms yielded similar results indicating the general applicability of the present findings. Scanning electron microscopy revealed that vermicomposting causes the otherwise robust and regular surface of prosopis leaves to get withered, thereby increasing their surface areas and making them more amenable to biodegradation.

KEYWORDS:

• Prosopis
• vermicompost
• allelopathy
• xerophtye
• organic fertiliser

Acknowledgements

SAA thanks the Council of Scientific and Industrial Research (CSIR), New Delhi, for the Emeritus Scientist grant (21(1034)/16/EMR-II).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Council of Scientific and Industrial Research India, New Delhi.