Effect of land use system and altitude on carbon stability in naturally occurring clay-organic complex in soils of Arunachal Pradesh in the Eastern Himalaya, India

ABSTRACT

This study assessed the effect of land use systems (rice-fallow, bamboo, mandarin and forest) along an altitude gradient (<500, 500–1000 and > 1000 m asl) and soil depth (0–15, 15–30 and 30–45 cm) on C stability in naturally occurring clay-organic complex (NOCOC) and their relationship with soil properties. The C stability in NOCOC (1/k) was determined from desorption rate constant (k) of humus-C by sequential extraction and was correlated with soil properties across the altitude. The C stability in NOCOC decreased (34%) with increasing soil depth from 0–15 to 30–45 cm. Across the altitudes, highest C stability in NOCOC was at > 1000 m asl (8.37 h) which was 12.7 and 9.4% higher than 500–1000 and < 500 m asl, respectively. Irrespective of soil depth and altitude, forest (5.30 h) showed the greatest C stability in NOCOC followed by mandarin (4.64 h), bamboo (4.20 h) and rice-fallow (3.85 h). Measurable soil properties could explain 90–94% variability of C stability in NOCOC across the altitude. Furthermore, C stability in NOCOC increased macroaggregate formation (0.25 mm) and ensured greater physical, chemical and microbial protection of organic C in soil.

KEYWORDS:

• Climate
• land use systems
• clay-organic complex
• soil properties
• macroaggregate formation

Acknowledgments

Authors are thankful to Division of Soil Science and Agricultural Chemistry, ICAR -IARI, New Delhi for accepting this project and providing laboratory facilities.

Disclosure statement

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

Data availability statement

Data is available on request.

Additional information

Funding

The work was supported by Department of Science and Technology, Ministry of Science and Technology, Government of India through DST–Inspire Fellowship.