Due to the reduction of cattle farming, the Finnish agricultural sector currently needs solutions to replace animal manure with new sustainable alternatives. This problem is especially acute for organic farms, which need livestock manure to improve soil fertility and soil organic carbon (SOC) to sustain yield. On the other side, plywood manufacturers aim to find ways to reuse waste fractions such as sandy, wet spruce bark waste. To address both issues, a new soil conditioner was developed from crushed bark (CB) and approved for organic farming by the Finnish Food Authority. To test the advantages of CB in organic wheat production, we conducted a two-year field experiment on a farmer’s field in Mikkeli (Finland) on loamy sand with moderate soil fertility (C 3.5%, C/N ratio 17, pH 6.2). CB (organic matter 80%, C/N ratio 78, pH 5.7-6.0) at 40 t ha^–1 was applied either in the first year of the experiment or in both years. In addition to CB, half the plots received base ash (4 t ha^–1) obtained from a power plant using wood to maintain the optimal soil pH. All plots were fertilised annually with commercial organic fertilisers. The control plots received no CB or base ash. A one-year application of CB with base ash statistically significantly increased the grain yield by 800 kg ha^–1 and grain N uptake by about 10 kg ha^–1 in the following growing season compared with the control. In terms of grain yield quality, a one-year application of CB with or without base ash already showed an improvement of 1000 seed weight by 2 g in the first year, and the effect was even more pronounced in the second year of the experiment. Hectolitre weight was increased in the following year after application of CB with base ash. In contrast, a two-year application of CB either alone or with base ash caused no changes in grain yield, N uptake, or yield quality compared with the control. The results indicate that the use of spruce CB with a high C/N ratio as soil conditioner in a large amount may be beneficial in terms of yield and quality when it is applied only once, but not twice in successive years. Future studies need to focus on the long-term residual effects of CB on productivity, as well as soil parameters such as SOC, cation exchange capacity, and soil microbial activity.

Highlights
- Crushed bark (C/N ratio 78) - a side stream of plywood manufacture - was tested in a two-year organic field experiment.
- A one-year (40 t ha^–1) application of crushed bark with base ash increased yield and the quality of organic wheat.
- Residual effects of a one-year application were pronounced.
- Crushed bark application in two successive years provided no benefits for organic wheat production.

由于养牛业的减少，芬兰农业部门目前需要用新的可持续替代品替代动物粪便的解决方案。这个问题对于有机农场来说尤其严重，它们需要牲畜粪便来提高土壤肥力和土壤有机碳 (SOC) 以维持产量。另一方面，胶合板制造商的目标是找到重新利用废物部分的方法，例如沙质、湿云杉树皮废物。为了解决这两个问题，芬兰食品局批准了一种新的土壤改良剂，采用压碎的树皮 (CB) 进行有机农业。为了测试 CB 在有机小麦生产中的优势，我们在 Mikkeli（芬兰）的一个农民田地中，在中等肥力（C 3.5%，C/N 比 17，pH 6.2）的壤质沙地上进行了为期两年的田间试验。CB（有机物 80%，C/N 比 78，pH 5.7-6.0）在 40 吨公顷^–1要么在实验的第一年应用，要么在两个年份都应用。除了 CB 之外，一半的地块还使用了从发电厂获得的基灰（4 t ha ^–1），使用木材来保持最佳土壤 pH 值。所有地块每年都用商业有机肥料施肥。对照地块没有 CB 或基础灰分。一年施用含基灰的 CB 在统计学上显着增加了 800 kg ha ^–1的粮食产量和约 10 kg ha ^{–1 的}粮食吸氮量在接下来的生长季节与对照相比。在籽粒产量品质方面，无论有无基灰，1年施用CB已显示第一年提高1000粒重2克，第二年效果更显着。在使用含基灰的 CB 后，第二年增加了百升重量。相比之下，与对照相比，单独或与基灰一起施用两年的 CB 不会导致谷物产量、氮吸收或产量质量发生变化。结果表明，大量使用高C/N比云杉CB作为土壤改良剂，仅施用一次，连续施用两次，可能对产量和质量有益。未来的研究需要关注 CB 对生产力的长期残余影响，

亮点
- 压碎的树皮（C/N 比 78） - 胶合板制造的一个侧流 - 在为期两年的有机田间试验中进行了测试。
- 一年（40 t ha ^–1）使用粉碎的树皮和基灰可提高有机小麦的产量和质量。
- 一年申请的残留影响是明显的。
- 连续两年使用碎树皮对有机小麦生产没有任何好处。