Verringerung von Ammoniakemissionen durch Gülleansäuerung auf dem Feld: Teilnahmebereitschaft von Landwirten an Förderprogrammen

This article sought to determine farmers’ willingness to join a hypothetical support scheme for slurry acidifica-tion during spreading. Slurry acidification is a novel technique to reduce ammonia emissions, which has been pioneered in Denmark. In an online discrete choice survey of German livestock farmers, the re-spondents were asked to choose between different pol-icy schemes to promote the use of acidification tech-niques and an opt-out option. The support schemes were characterized by the following attributes: cost share, expected emission reduction as well as a relief from, and a tightening of, the German Fertilizer Ordi-nance. The relief was a waiver of the legal requirement to incorporate slurry immediately after spreading. The tightening related to the provision to account for the additional nitrogen in a farmer’s fertilizer planning. The data was estimated using a mixed logit model and latent class analysis. The estimated probability of choosing a support scheme was 90 % in the mixed logit estimation. All attributes were crucial for the decision to use acidification techniques during slurry spreading. Higher emission reduction increased the chances of participation in a support scheme significantly. Fur-thermore, the cost share offered and the exemption from the requirement to incorporate slurry immediately after spreading had a significantly positive impact on farmers’ willingness to participate. By contrast, the more of the extra nitrogen contained in acidified slurry had to be accounted for in a farmer’s fertilizer plan-ning, the lower the probability of participation.

本研究旨在探究农户参与假设性的撒施过程粪浆酸化（slurry acidification）支持计划的意愿。粪浆酸化是一项旨在减少氨气排放的新兴技术，最早由丹麦率先应用。
本研究针对德国畜禽养殖户开展了线上离散选择调查，要求受访者在多种推广酸化技术的政策方案与退出选项之间做出选择。此类支持方案具备以下属性：成本分担比例、预期减排量，以及《德国肥料条例（German Fertilizer Ordinance）》的豁免与收紧条款。
所谓豁免，即豁免养殖户在撒施粪浆后需立即将其混入土壤的法定要求；而收紧条款则要求养殖户在肥料规划中核算酸化粪浆中的额外氮含量。
本研究采用混合logit模型（mixed logit model）与潜在类别分析（latent class analysis）对调研数据进行估计。混合logit模型的估计结果显示，农户选择支持方案的概率为90%。
所有属性均对农户在撒施粪浆过程中采用酸化技术的决策具有关键影响。更高的预期减排量可显著提升农户参与支持方案的概率。此外，提供的成本分担比例以及撒施后无需立即混入粪浆的豁免条款，均对农户的参与意愿产生了显著正向影响。与之相反，农户在肥料规划中需核算的酸化粪浆额外氮含量越高，其参与支持方案的概率就越低。