A number of policies proposed to increase soil organic matter (SOM) content in agricultural land as a carbon sink and to enhance soil fertility. Relations between SOM content and crop yields however remain uncertain. In a recent farm survey across six European countries, farmers reported both their crop yields and their SOM content. For four widely grown crops (wheat, grain maize, sugar beet and potato), correlations were explored between reported crop yields and SOM content (N = 1264). To explain observed variability, climate, soil texture, slope, tillage intensity, fertilisation and irrigation were added as co-variables in a linear regression model. No consistent correlations were observed for any of the crop types. For wheat, a significant positive correlation (p < 0.05) was observed between SOM and crop yields in the Continental climate, with yields being on average 263 ± 4 (95% CI) kg ha⁻¹ higher on soils with one percentage point more SOM. In the Atlantic climate, a significant negative correlation was observed for wheat, with yields being on average 75 ± 2 (95%CI) kg ha⁻¹ lower on soils with one percentage point more SOM (p < 0.05). For sugar beet, a significant positive correlation (p < 0.05) between SOM and crop yields was suggested for all climate zones, but this depended on a number of relatively low yield observations. For potatoes and maize, no significant correlations were observed between SOM content and crop yields. These findings indicate the need for a diversified strategy across soil types, crops and climates when seeking farmers’ support to increase SOM.

提出了许多旨在增加农田中土壤有机质（SOM）含量作为碳汇并提高土壤肥力的政策。然而，SOM含量与农作物产量之间的关系仍然不确定。在最近对六个欧洲国家进行的农场调查中，农民报告了他们的农作物产量和SOM含量。对于四种广泛种植的作物（小麦，谷物玉米，甜菜和马铃薯），研究了报告的作物单产与SOM含量之间的相关性（N = 1264）。为了解释观测到的变异性，将线性回归模型中的协变量添加了气候，土壤质地，坡度，耕作强度，施肥和灌溉作为协变量。没有观察到任何作物类型的一致相关性。对于小麦，显着正相关（p 在大陆性气候下，SOM与作物单产之间的差异<0.05。在SOM高一个百分点的土壤上，平均单产高263±4（95％CI）kg ha ^-1。在大西洋气候中，观察到小麦具有显着的负相关性，在土壤中的平均单产高出一个百分点，平均单产降低了75±2（95％CI）kg ha ^-1（p  <0.05）。对于甜菜，显着正相关（p 建议在所有气候区的SOM和作物单产之间<<0.05），但这取决于许多相对较低的单产观测值。对于马铃薯和玉米，未观察到SOM含量与农作物产量之间的显着相关性。这些发现表明，在寻求农民支持以增加SOM时，需要针对土壤类型，作物和气候采取多样化的策略。