Abstract Perennial ryegrass starts growing when soil temperatures reach 5.5°C for five consecutive days; applying N fertilizer before this risks environmental losses. To test whether daffodil flowering signified when to apply N fertilizer, farmers volunteered to take part in a citizen science study. The PROSOIL project used a “citizen science”, participatory approach to create farmer‐informed science, aiming to increase awareness of the importance of soil health. In 2014, over 300 farmers completed a “How do you manage your soil” survey. The survey included a question on the use of daffodils (Narcissus spp.) to indicate the best time to apply the first nitrogen fertilizer of the season, based on anecdotal feedback from farmers involved in the PROSOIL project. The survey recorded 7% of farmers based their first fertilizer application on when daffodils flowered. To increase farmer awareness of soil temperatures, we provided them with soil thermometers, held workshops and hosted interactive stands at agricultural events in 2014. In autumn 2014, farmers planted daffodil bulbs of the same variety, across Wales, and monitored soil temperatures. Farmers returned postcards once their daffodils were in flower, noting the soil temperature. An assessment of whether daffodil flowering date could indicate when to apply N fertilizer was made. Overall, in spring 2015, daffodils flowered when soil temperature was 6.4(±0.35)°C, suggesting daffodil flowering date is a more reliable indicator for fertilizer application, than first hypothesized. Findings show a scientific validation of local knowledge, regarding the use of daffodils to indicate the “not‐before” date for the first N fertilizer application.

中文翻译：

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农民应该根据水仙开花的时间施肥吗？利用“农民科学”方法了解土壤温度对威尔士春季施氮肥的影响

摘要 当土壤温度连续 5 天达到 5.5°C 时，多年生黑麦草开始生长；在这可能导致环境损失之前施用氮肥。为了测试水仙花开花是否意味着何时施氮肥，农民自愿参加一项公民科学研究。PROSOIL 项目使用“公民科学”、参与式方法来创建农民知情科学，旨在提高对土壤健康重要性的认识。2014 年，超过 300 名农民完成了“您如何管理土壤”调查。根据参与 PROSOIL 项目的农民的轶事反馈，调查包括一个关于使用水仙花 (Narcissus spp.) 的问题，以表明施用当季第一次氮肥的最佳时间。调查记录了 7% 的农民根据水仙花开花的时间进行第一次施肥。为了提高农民对土壤温度的认识，我们在 2014 年为他们提供了土壤温度计、举办了研讨会并在农业活动中举办了互动展台。 2014 年秋季，农民在威尔士各地种植了相同品种的水仙球茎并监测了土壤温度。一旦他们的水仙开花，农民们就会寄回明信片，注意土壤温度。对水仙花开花日期是否可以指示何时施用氮肥进行了评估。总体而言，2015 年春季，水仙花在土壤温度为 6.4(±0.35)°C 时开花，表明水仙花开花日期是比最初假设更可靠的施肥指标。调查结果显示了对当地知识的科学验证，