# The Evolutionary Traits of Carbon Emissions from the Planting Industry in Beijing, China
## 4 Discussion
### Factors Affecting Carbon Emissions from the Planting Industry  
The results of this study show that the carbon emissions from the planting industry in Beijing have generally shown a downward trend since 2000. By 2023, the carbon emissions from agricultural inputs and N\({}_{2}\)O from farmland decreased by 59.88% and 74.52%, respectively. The 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 have decreased by 70.43%. This study found that changes in carbon emissions from Beijing's planting industry were correlated with changes in carbon source composition. The carbon emissions from agricultural inputs and N\({}_{2}\)O emissions from farmland were the main sources of carbon emissions from the planting industry in Beijing, while the amount of fertilizer and agricultural film input directly affected the carbon emissions from agricultural inputs. Meanwhile, N\({}_{2}\)O carbon emissions from agricultural land were also significantly related to fertilizer inputs. This discovery provides a pathway for carbon reduction in the planting industry in Beijing.  
The changes in carbon emissions from Beijing's agriculture industry suggest that the reasons for these changes may be related to the evolution of Beijing's agricultural policies and the adjustment of its planting structure. According to the data from the Beijing Municipal Bureau of Statistics, the sown area of crops dropped from 457,300 \(\mathrm{hm^{2}}\) in 2000 to 143,800 \(\mathrm{hm^{2}}\) in 2022, and the pure amount of agricultural fertilizers and pesticides dropped from 179,000 tons and 5400 tons in 2000 to 66,100 tons and 2300 tons in 2022, respectively. The decline in the sown area and the quantity of agricultural inputs has led to a decline in carbon emissions from the planting industry. At the same time, before 2012, the increase in grain production mainly depended on a large amount of agricultural materials input, and then with the active implementation of policies, such as the \"double reduction of chemical fertilizers and pesticides\" and the development of green agriculture, as well as relevant control measures, the carbon emissions from the planting industry have been effectively controlled, and the total agricultural carbon emissions have shown a downward trend.  
In addition, the improvement of agricultural production methods and production technologies has promoted the green development of agriculture; optimized the management and use of water, fertilizers, and pesticides in the planting industry; and reduced the carbon emissions from the planting industry to a certain extent. This result is also consistent with others. Previous studies have found that agricultural carbon emissions have strong spatial heterogeneity, which was related to differences in natural conditions, production methods, production layout, planting structure, resource input, and technical level in different regions [13; 14; 15]. Meanwhile, some studies also believed that the level of agricultural economic development, agricultural structure, the scale of labor force, mechanization, and agricultural production efficiency were the main driving factors of agricultural carbon emissions [16; 17]. This study only expounded the possible influencing factors of carbon emissions in Beijing from the composition, while the quantitative relationship between carbon emissions and local planting structure, production layout, agricultural economy, labor force scale, production efficiency, and other factors will also be the focus of further in-depth research in the future.