Forests, Vol. 16, Pages 946: Impact of Long-Term Agroforestry Systems on Carbon Pools and Sequestration in Top and Deep Soil Layers of Semi-Arid Region of Western India

Forests doi: 10.3390/f16060946

Authors:
Mahesh Sirimalle
Chiranjeev Kumawat
Raimundo Jiménez-Ballesta
Ramu Meena
Kamlesh Kumar Sharma
Abhik Patra
Kiran Kumar Mohapatra
Arvind Kumawat

To explore the impact of different agroforestry systems on carbon sequestration, the carbon management index, and carbon fractions, a long-term (37 years) field trial was conducted using three tree-based agroforestry systems consisting of tree species, namely Acacia tortilis, Hardwickia binata, and Tecomella undulata, along with fallow land in a semi-arid region of India. The soil samples were taken at four distinct depths (0–15, 15–30, 30–60, and 60–90 cm) with eight replications and analyzed for soil total organic carbon (TOC), soil organic carbon fractions, soil carbon stocks, and the carbon management index (CMI). In the topsoil layer (0–30 cm), the Acacia tortilis-based agroforestry system recorded a total organic carbon (TOC) content of 4.09%, which was 42.5% higher than that of fallow land. In this layer, the active carbon pool (ACP) was more prominent than the passive carbon pool (PCP). Compared to fallow land, the ACP increased by 68.3%, 59%, and 53.6% for the Acacia tortilis-, Hardwickia binata-, and Tecomella undulata-based systems, respectively. Similarly, the PCP increased by 18.4%, 11.8%, and 8.2% for the same respective systems in the topsoil layer. For the 0–90 cm soil layer, the Acacia tortilis-based agroforestry system sequestered the highest amount of total organic carbon (39.34 Mg C ha−1), followed by agroforestry systems based on Hardwickia binata (37.86 Mg C ha−1), Tecomella undulata (36.99 Mg C ha−1), and fallow land (30.65 Mg C ha−1). Carbon sequestration is higher in the subsurface soil layers (30–90 cm) than in the surface layers. This trend is observed across all agroforestry systems. The carbon management index registered higher for the Acacia tortilis-based agroforestry system (166.58) at the top soil layer than others. Hence, long-term agroforestry systems could improve soil carbon storage and the carbon management index as compared to fallow land. A 37-year field study in a semi-arid region of India revealed that Acacia tortilis-based agroforestry significantly enhances soil carbon sequestration, active carbon pools, and the carbon management index, especially in deeper soil layers, compared to fallow land.

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