Enhancing biomass yield simultaneously with soil carbon (C) sequestration is a key aim of climate-smart cropping systems. Perennialization is believed to be a suitable mitigation strategy for climate change with the potential for enhancing soil C stocks. Based on a nine-year field experiment in Denmark, we measured the changes in soil C and nitrogen (N) stocks, biomass yield, and yield stability of three perennial (low-fertilized miscanthus, high-fertilized festulolium, and no N-fertilized grass-legume mixture) and two annual (continuous triticale and maize) cropping systems. We found that the changes in topsoil (0–20 cm) and 0–100 cm soil C stocks and topsoil N stocks varied significantly between cropping systems. Over nine years, topsoil C stocks increased by an average of 1.4 Mg C ha in the three perennial cropping systems, while they decreased by 3.4 Mg C ha in the two annual cropping systems. The 0–100 cm soil C stocks increased by 6.8 Mg C ha in the three perennial cropping systems and increased by 2.3 Mg C ha in the triticale system, but decreased by 2.5 Mg C ha in the maize system. Topsoil N stocks increased by 0.18 Mg N ha in three perennial systems while they decreased by 0.08 Mg N ha in the two annual cropping systems. Changes in 0–100 cm soil N stocks did not differ significantly between cropping systems. Miscanthus, festulolium, and maize showed the highest biomass yield (17.1, 16.7, and 16.4 Mg ha year, respectively). There were no significant differences among cropping systems in yield stability. This study demonstrated the potential of perennial cropping systems in obtaining higher soil C stocks compared with annual cropping systems while maintaining high biomass yield, supporting perennialization as a promising option for climate-smart agriculture.

中文翻译：

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多年生耕作系统比一年生系统增加了表土碳和氮储量——一项为期九年的实地研究

同时提高生物量产量和土壤碳固存是气候智能型种植系统的一个关键目标。多年生化被认为是一种合适的气候变化缓解策略，具有增加土壤碳储量的潜力。基于丹麦为期九年的田间试验，我们测量了三种多年生植物（低肥芒草、高肥羊茅和不施氮肥）的土壤碳和氮（N）储量、生物量产量和产量稳定性的变化。草-豆类混合物）和两种一年生（连作黑小麦和玉米）种植系统。我们发现表土（0-20厘米）和0-100厘米土壤碳库和表土氮库的变化在不同的耕作制度之间存在显着差异。九年来，三个多年生种植系统的表土碳储量平均增加了 1.4 毫克碳公顷，而两个一年生种植系统的表土碳储量平均减少了 3.4 毫克碳公顷。三种多年生种植系统的0-100 cm土壤碳储量增加了6.8 Mg C ha，黑麦系统增加了2.3 Mg C ha，但玉米系统减少了2.5 Mg C ha。三个多年生系统中表土氮储量增加了 0.18 Mg N ha，而两种一年生系统中表土氮储量减少了 0.08 Mg N ha。0-100 厘米土壤氮储量的变化在不同耕作制度之间没有显着差异。芒草、羊茅和玉米的生物量产量最高（分别为 17.1、16.7 和 16.4 毫克公顷年）。不同耕作制度的产量稳定性没有显着差异。这项研究表明，与一年生种植系统相比，多年生种植系统在获得更高的土壤碳储量方面具有潜力，同时保持高生物量产量，支持多年生化作为气候智能型农业的一个有前途的选择。