发表机构
Indian Institute of Science (IISc)（印度科学理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过合同设计视角，利用强化学习求解POMDP模型，发现利润最大化的聚合机构会加剧而非缓解小农户在碳农业中的排斥，并提出按面积比例MRV成本可消除该差异。
AI 中文摘要
农业土壤是一个巨大的未开发碳汇。碳农业正成为一种有前景的实践，以挖掘这一潜力。小农户主导着南亚和撒哈拉以南非洲的农业，是通过碳农业扩大气候减缓规模的关键。具有讽刺意味的是，现实世界中的碳项目在很大程度上未能惠及他们。我们通过合同设计的视角研究这一重要差距。一个聚合机构向异质的小农户群体提供单一集合合同，这些农户拥有私人采用成本（逆向选择）并付出不可观测的努力（道德风险），农艺结果在多季节中演变。我们将这一演化中的合同问题表述为部分可观测马尔可夫决策过程（POMDP），并使用强化学习来学习一个动态利润最大化的合同。我们分析了聚合机构在各种条件下的表现。我们发现，利润最大化的聚合机构不仅继承了小农户的排斥，还加剧了这种排斥。在大农场上，聚合机构实现了87.7%的可实现采用率，而在小农场上仅为8.2%。每公顷的测量、报告和核查（MRV）成本随着农场规模的增大而下降，聚合机构的集合合同加剧了这一梯度而非抵消它。一个使MRV成本纯粹按面积比例的反事实消除了这一差异。我们的结果和模拟可以指导合同和政策设计，向小农户开放碳收入，同时使农业土壤能够大规模地促进气候减缓。
英文摘要
Agricultural soils are a major untapped carbon sink. Carbon farming is emerging as a promising practice for tapping this potential. Smallholder farmers, who dominate agriculture across South Asia and sub-Saharan Africa, are key to scaling climate mitigation via carbon farming. It is ironic that real-world carbon programs largely fail to reach them. We study this important gap through the lens of contract design. An aggregator offers a single pooled contract to a heterogeneous population of smallholder farmers who have private adoption costs (adverse selection) and exert unobserved effort (moral hazard), with agronomic outcomes evolving over multiple seasons. We formulate this evolving contracting problem as a POMDP and use reinforcement learning to learn a dynamic profit-maximising contract. We analyse the performance of the aggregator under various conditions. We find that a profit-maximising aggregator does not merely inherit the exclusion of smallholders, it amplifies it. On large farms the aggregator realises 87.7% of achievable adoption, against only 8.2% on smallholdings. Per-hectare Measurement, Reporting and Verification (MRV) costs fall as farm size rises, and the aggregator's pooling contract compounds this gradient rather than offsetting it. A counterfactual that makes MRV costs purely area-proportional eliminates this disparity. Our results and simulation can guide contract and policy design that opens carbon income to smallholders while enabling agricultural soils to contribute to climate mitigation at scale.
Comments14 pages, 2 figures
