Achieving Land Degradation Neutrality Through Tea Plantation: Future Prospect for Combating Climate Change in the Northeast Himalayan Region of India

Tea cultivation, being a woody perennial land-use, has an enormous potential to sequester a vast amount of carbon (C) in its biomass and soil rhizosphere. The Northeast Himalayan region (NEH) of India is a traditional tea growing belt, thus the impact of long-term climate change can be mitigated through the enrichment of soil organic carbon (SOC). Tea cultivation can also contribute to land degradation neutrality (LDN) by restoring degraded lands and provide higher economic gains and better livelihood to the small and marginal farmers of the region. The present study was conducted to understand the change in SOC dynamics under climate change (CC) conditions using the RothC simulation model in the Brahmaputra plain of upper Assam state. The model was used to simulate SOC stock change for a period of 10 years (2010–2020) under the baseline climate conditions, and for a period of 30 years (2021–2050) with four CC scenarios for temperature (T) and rainfall (R) available for Assam state. The SOC stock under the baseline climate increased by 8.4% from 2010 to 2020. However, simulations under CC scenarios indicated a negative impact on SOC stock. In particular, SOC stock declined by 3.7, 4.4, 4.5 and 4.8% in CC1 (T + 1.7 °C, R + 5%), CC2 (T + 1.7 °C, R + 10%), CC3 (T + 2.0 °C, R + 5%) and CC4 (T + 2.0 °C, R + 10%), respectively. The average decline in SOC stocks was 4.3% during 2021–2050. Interestingly, the study also revealed that the decline in SOC stock was more marked during the initial 5 years and then stabilized under future CC; thus, the adverse effects of CC seem to be mitigated. Our study identified the high resilience of SOC under long-term tea plantation toward CC. We also recommend that long-term tea plantations are intercropped with other economically important crops to store higher amounts of SOC, contribute to LDN and provide economic stability to the farmers of the region.