Table_1_Carbon dioxide equivalent emissions from corn silage fermentation.DOCX

The European Climate Law recently codified the goal for European climate neutrality by 2050, highlighting the need for sustainable farming practices within a robust and transparent carbon dioxide equivalent (CO2e) accounting system. In the present study, a series of equations were proposed for the estimation of CO2e emissions from corn silage fermentation. Systematic review of previous meta-analyses of corn silage fermentation identified the mean and standard deviation statistics for key model inputs of acetic acid, ethanol, lactic acid, ammonia, and volatile-corrected dry matter loss. Estimates of CO2e emissions were determined for a mock dataset comprising 1,000 iterations of randomly-generated values for each metric in accordance with mean and variance statistics of the source data. Estimates for CO2e emissions of corn silage based on meta-analysis review of laboratory experiments were 1.9 ± 5.6% (GWP20) and 0.2 ± 5.5% (GWP100) of silage dry matter. Furthermore, model results demonstrated a precedent for CO2 recycling by silage microorganisms, which was supported by genome annotation of strains belonging to common silage species. Linear model equations for GWP20 and GWP100 with inputs and outputs in mg kg−1 silage dry matter were developed, where inputs are acetic acid (A), ethanol (E), lactic acid (L), and volatile corrected dry matter loss (DV). Linear equations are (for GWP20; Eq. 11):
GWP20=−3626.1−0.04343A+0.8011E−0.03173L+1.46573DV
and for GWP100; Eq. 12:
GWP100=−8526.10−0.22403A−0.11963E−0.03173L+1.46573DV.

欧盟气候法案（European Climate Law）近日正式将欧盟2050年气候中和目标纳入法典，强调了在健全且透明的二氧化碳当量（CO₂e）核算体系内推行可持续农业实践的必要性。本研究针对玉米青贮发酵过程的二氧化碳当量排放估算，提出了一系列计算公式。通过系统梳理既往玉米青贮发酵的荟萃分析成果，本研究获取了乙酸、乙醇、乳酸、氨以及挥发性校正干物质损失等关键模型输入参数的均值与标准差统计量。基于源数据的均值与方差统计特征，本研究针对各指标生成1000组随机取值的模拟数据集，据此开展二氧化碳当量排放估算。基于实验室实验荟萃分析得到的玉米青贮二氧化碳当量排放估算结果为青贮干物质的1.9±5.6%（GWP20，全球变暖潜能值20年尺度）与0.2±5.5%（GWP100，全球变暖潜能值100年尺度）。此外，模型结果证实了青贮微生物可实现二氧化碳循环的先例，该结论得到了常见青贮菌种菌株的基因组注释数据支撑。本研究开发了以mg·kg⁻¹青贮干物质为单位的GWP20与GWP100线性模型方程，输入参数为乙酸（A）、乙醇（E）、乳酸（L）及挥发性校正干物质损失（DV）。其中针对GWP20的线性方程（式11）为：
GWP20=−3626.1−0.04343A+0.8011E−0.03173L+1.46573DV
针对GWP100的线性方程（式12）为：
GWP100=−8526.10−0.22403A−0.11963E−0.03173L+1.46573DV。