Abstract

Previous studies have confirmed the agricultural stage as an important contributor to total tea life cycle greenhouse gas (GHG) emissions. We therefore focus on the growing and processing of black tea and evaluate the GHG reduction potential of possible agricultural management interventions for tea produced from Unilever’s tea estates and factories in Kenya. A baseline GHG footprint was calculated using data collected over four years. Potential interventions to reduce the GHG footprint per kg of black tea focused on key drivers (yield and fertiliser use) of the GHG footprint. These interventions and their effects on production are evidence-based but hypothetical and relate to possible changes in: (1) Harvesting practices; (2) Fertiliser application (timing) and (3) Organic production. Improvements in fertiliser application and harvesting practices could potentially deliver 16% and 9% reduction in GHG emissions, respectively. Under favourable conditions (sourcing fertiliser locally and no yield decline), changing to organic production could theoretically deliver 25% reduction in GHG emissions. However, under less favourable conditions (European sourced fertiliser and 30% yield decline), GHG emissions could increase by 41%. The availability of locally sourced organic fertiliser, sufficient to maintain nitrogen application rates, is seen as the biggest challenge in delivering sustainable organic tea cultivation.

摘要

先前的研究已经证实，农业阶段是整个茶生命周期温室气体（GHG）排放的重要贡献者。因此，我们专注于红茶的种植和加工，并评估了联合利华肯尼亚茶园和工厂生产茶的可能农业管理干预措施所带来的温室气体减排潜力。使用四年来收集的数据计算了基准GHG足迹。减少每公斤红茶的温室气体足迹的潜在干预措施集中在温室气体足迹的关键驱动因素（产量和肥料使用）上。这些干预措施及其对生产的影响是基于证据的，但是是假设性的，并且与以下方面的可能变化有关：（1）采伐方式；（2）施肥（定时）和（3）有机生产。肥料施用和收割方法的改进可能分别使温室气体排放减少16％和9％。在有利的条件下（本地采购肥料且单产没有下降），理论上改用有机生产可以减少25％的温室气体排放。但是，在不利条件下（欧洲采购化肥，产量下降30％），温室气体排放量可能增加41％。足以维持氮肥施用量的本地有机肥料的可用性，被视为实现可持续有机茶种植的最大挑战。从理论上讲，改用有机生产可以减少25％的温室气体排放。但是，在不利条件下（欧洲采购化肥，产量下降30％），温室气体排放量可能增加41％。足以维持氮肥施用量的本地有机肥料的可用性，被视为实现可持续有机茶种植的最大挑战。从理论上讲，改用有机生产可以减少25％的温室气体排放。但是，在不利条件下（欧洲采购化肥，产量下降30％），温室气体排放量可能增加41％。足以维持氮肥施用量的本地有机肥料的可用性，被视为实现可持续有机茶种植的最大挑战。