Regenerative Agriculture in Tea Systems: A Review of Soil Degradation, Nutrient Management, Climate Risk and the Role of Certification-Based Implementation, with Evidence from India

Tea (Camellia sinensis (L.) Kuntze) is a long-lived perennial crop subject to climate variability, soil degradation and the environmental consequences of intensive nutrient use. This critical narrative review synthesises evidence on climatic constraints to tea production, soil acidification and carbon dynamics, nitrogen management and greenhouse-gas emissions, and the relevance of regenerative agriculture and voluntary sustainability standards to Indian tea systems. Published studies indicate that prolonged high nitrogen inputs can intensify soil acidification and nitrogen losses, although agronomically appropriate rates differ with site conditions, yield targets and tea type. Tea soils can be substantial sources of nitrous oxide, while the relative contributions of field activities and factory processing depend on the carbon-accounting boundary. Organic amendments, diversified vegetation management and more efficient fertilisation may improve particular soil indicators, but long-term replicated evidence for integrated regenerative packages in Indian tea remains limited. As an illustrative, non-experimental case, monitoring summaries from an Indian tea regenerative agriculture (REGEN) programme are considered. The programme reports a mean baseline soil organic carbon concentration of 1.06%, pH of 4.73, made-tea yield of 1,828 kg ha⁻¹ and synthetic nitrogen application of 131.8 kg N ha⁻¹. Its operator-reported early summaries indicate relative changes of more than 5% in soil organic carbon, 18% in culturable microbial counts, 3% in productivity, −15% in synthetic nitrogen and approximately −21% in field/source-point greenhouse-gas emission intensity. These figures lack documented matched-cohort denominators, uncertainty estimates and independent verification, and cannot establish effects attributable to the programme. The principal research priority is longitudinal, independently assessed measurement of soil carbon stocks, nitrogen balances, productivity and emissions under comparable field and factory boundaries.