Payments for Environmental Services (PESs) are increasingly used to foster farmers’ adoption of greener practices, but their effectiveness is often undermined by low enrollment. In a large randomized field experiment (N = 20,000), we test several non-monetary incentives to increase enrollment into the French implementation of the Agri-Environmental Schemes program of the European Union. We find that sending 10,000 information letters triggers the enrollment of 75 ± 52 farmers at a cost of 102 $\pm\ $71 Euros/new enrollee. Pre-stamped reply forms increase contacts with caseworkers but fail to raise enrollment. Testimonies by other farmers seem to decrease the effectiveness of the letters. Diffusion effects could increase the impact of our non-monetary incentives by 40% to 50% and decrease the cost of an additional enrollee by around 30%.

中文翻译：

---

增加环境服务付费入学人数的非货币激励措施

环境服务付费 (PES) 越来越多地用于促进农民采用更环保的做法，但其有效性往往因入学率低而受到影响。在一项大型随机现场实验（N = 20,000）中，我们测试了几种非货币激励措施，以增加法国实施欧盟农业环境计划计划的入学率。我们发现发送 10,000 封信息信会触发 75 ± 52 名农民的注册，成本为 102 $\pm\ $71 欧元/新注册者。预先盖章的回复表格增加了与个案工作者的联系，但未能提高入学率。其他农民的证词似乎降低了信件的有效性。扩散效应可以将我们的非货币激励措施的影响提高 40% 至 50%，并将额外参与者的成本降低约 30%。