# The Evolutionary Traits of Carbon Emissions from the Planting Industry in Beijing, China
## 5 Conclusions  
This study provides a detailed calculation of the annual carbon emissions, carbon emissions composition, carbon production, economic and ecological benefits, and changing trends of Beijing's planting industry in the past 23 years, providing important basic data for the continuous monitoring of carbon emissions from Beijing's planting industry. In 2023, the carbon emissions from the planting industry in Beijing were 256,400 tons, of which the carbon emissions from agricultural inputs, N\({}_{2}\)O, and CH\({}_{4}\) were 149,300, 105,200, and 2000 tons, respectively. From 2000 to 2023, the total carbon emissions from the planting industry in Beijing showed a downward trend. Compared with 2000, carbon emissions from agricultural inputs and N\({}_{2}\)O of farmland in 2023 decreased by 59.88% and 74.52%, respectively, Carbon emissions of CH\({}_{4}\) from rice cultivation were only 2.38% of those in 2000, and the total carbon emissions from the planting industry in Beijing decreased by 70.43%. The identified factors affecting agricultural emissions in this study provide a possible pathway for carbon reduction in Beijing's agriculture. The changes in carbon emissions from agriculture in Beijing are related to the changes in carbon source composition. The carbon emissions from agricultural inputs and N\({}_{2}\)O of farmland accounted for 50.85% and 47.95% of the total level from the planting industry on average, respectively, which were the main sources of carbon emissions from the planting industry in Beijing. The amount of fertilizer and agricultural film input directly affect the carbon emissions from agricultural inputs. Meanwhile, carbon emissions of N\({}_{2}\)O from agricultural land are also significantly related to fertilizer inputs. Reducing inputs for agriculture and sources of N2O from farmland is an important way to reduce carbon emissions from agriculture in Beijing, providing a way to support carbon reduction in agriculture. Based on the above research results, some suggestions for reducing the carbon emissions from Beijing's planting industry are as follows. Firstly, optimize the planting structure and reduce fertilizer input through multiple channels to reduce carbon emissions. This study proposes that fertilizers are one of the important factors affecting carbon emissions from agricultural inputs, and reducing the amount of fertilizer input can be considered to reduce carbon emissions. One way is to reduce the cultivation of high-nitrogen crops. As is well known, the amount of fertilizer applied per unit area for vegetables is much higher than that for grain crops. The 2016 annual report on the long-term monitoring of farmland quality in the suburbs of Beijing showed that the total input of organic and inorganic nutrients in grain fields was 522.0 kg/hm\({}^{2}\); in open-field vegetable fields and facility vegetable fields it was 2050.5 kg/hm\({}^{2}\) and 3427.5 kg/hm\({}^{2}\), respectively. However, the size of vegetable planting areas in Beijing has increased from 21.3% in 2010 to 32.39% in 2023, showing a clear and rapid upward trend. The increase in the size of vegetable planting area has led to a relatively high level of agricultural fertilizer input in Beijing. Therefore, appropriately reducing the vegetable planting area, increasing the grain field area, and optimizing the planting structure can reduce the total amount of fertilizer input, thereby reducing carbon emissions in the planting industry. In addition, nitrogen-fixing crops can reduce nitrogen fertilizer input by fixing a certain amount of nitrogen in their roots. The cultivation of carbon sequestration crops can offset carbon emissions due to their strong carbon sequestration capacity. Increasing the number of crops with strong nitrogen fixation and carbon sequestration capabilities can help reduce carbon emissions. For example, increasing the planting area of beans and C4 crops (such as corn, sunflower, etc.