Carbon sequestration potential of coconut-based intercropping systems under humid tropical conditions of Kerala, India

Abstract

In Kerala, India’s humid tropics, coconut (Cocos nucifera L.) plantations dominate the land-use system;
however, monocropping techniques frequently lead to inefficient use of biomass resources and land.
Introducing perennial plantation crops within the coconut plantation led to enhance the carbon storage and farm
sustainability. This study quantified and compared carbon sequestration potential in coconut monoculture and
coconut-based intercropping systems with cocoa (Theobroma cacao) and nutmeg (Myristica fragrans) under
humid tropical conditions in Kerala, India. The experiment was conducted at Kerala Agricultural University,
Vellanikkara, from September 2024 to September 2025, with five treatments: coconut monocrop (WCT), hybrid
monocrop (Dwarf × Tall), coconut-cocoa, coconut-nutmeg and a non-cropped control. Above ground biomass
was estimated using species-specific allometric equations, while soil organic carbon (SOC) was measured at
0-15, 15-30 and 30-45 cm depths. Total carbon stock, obtained by combining above ground and soil carbon,
varied significantly among systems. The coconut-cocoa system recorded the highest total carbon stock (156.79
t ha-1), followed by coconut-nutmeg (110.95 t ha-1), coconut monoculture (82.89 t ha-1) and hybrid monoculture
(72.48 t ha-1), while in non-cropped control recorded only 13.91 t ha-1. SOC declined with depth, with maximum
values in the 0-15 cm layer. Intercropped systems also showed lower bulk density than the non-cropped control,
indicating improved soil physical condition. The results underscore coconut-based intercropping, particularly
with cocoa, as an effective plantation management strategy for enhancing carbon sequestration and promoting
climate-resilient, sustainable coconut production.