## 5 Conclusions  
Using remote sensing image data, meteorological observations, digital elevation models, and land use data, this study employed the CASA model and mean value method to simulate corn NPP in the Fen River Basin throughout the corn growing season, spanning from May to October 2020. Subsequently, an analysis was conducted to determine the spatiotemporal variations inherent in NPP. This analysis encompassed an assessment of spatiotemporal variation characteristics. Additionally, correlation analysis was employed to investigate the impact of various environmental conditions on corn NPP in the Fen River Basin. Furthermore, this study applied a biomass inversion model driven by NPP, considering the principles of photosynthesis in green plants, to determine the coefficients of the relationships between aboveground biomass, carbon sequestration, and NPP. As a result, estimates for aboveground biomass and carbon sequestration of corn in the Fen River Basin were generated, with subsequent analysis of their spatial distribution patterns. The primary findings and outcomes of this study are summarized as follows:  
1. In terms of the temporal aspect, the variation in corn NPP in the Fen River Basin from May to October 2020 exhibited a clear and consistent pattern. This pattern follows a unimodal trend characterized by an initial increase, followed by a subsequent decrease. The average NPP value over this period amounted to 368.65 gC/m\({}^{2}\), with the highest peak observed in August at 131.71 gC/m\({}^{2}\) and the lowest point recorded in October at 11.53 gC/m\({}^{2}\). Regarding the spatial distribution, the distribution pattern of corn NPP demonstrated notable features. Overall, the NPP of corn across the Fen River Basin during May to October 2020 ranged from 0.34 gC/m\({}^{2}\) to 177.99 gC/m\({}^{2}\). The middle section of the basin exhibited the most significant carbon sequestration capability and NPP, followed by the lower and upper sections of the Fen River Basin. 2. Examining the spatial distribution of August corn NPP within the Fen River Basin from 2011 to 2020 revealed values spanning from 14.40 gC/m\({}^{2}\) to 181.59 gC/m\({}^{2}\). Notably, the NPP for August in the Fen River Basin in 2016 was generally lower than that in other years, whereas the NPP for August in the Fen River Basin in 2011 was generally higher than that in other years. In terms of temporal analysis, mean NPP values fluctuated within the range from 94.23 gC/m\({}^{2}\) to 154.12 gC/m\({}^{2}\), displaying an overall upward trend. Notably, the carbon sequestration capacity of corn crops in the Fen River Basin exhibited a positive development, particularly after 2017. During this period, both the mean and maximum values increased, whereas the minimum value decreased, indicating a pronounced enhancement in the carbon sequestration capacity. 3. Distinct reactions of corn NPP to climatic parameters were evident within the Fen River Basin. Spatially, there was a consistent positive correlation with air temperature, with a slight positive correlation being the dominant factor comprising 92.07% of the correlation. For precipitation, the predominant response was a positive correlation, with a significant positive correlation accounting for 38.22% of the total. Conversely, solar radiation exhibited a negative correlation (50.80%) and a positive correlation (48.29%). 4. In the Fen River Basin in 2020, the numerical distributions of corn biomass and total carbon sequestration were normally distributed and their spatial distributions were similar to each other. Specifically, the aboveground corn biomass ranged from 9.76 to 138.26 g/m\({}^{2}\), with 97.37% of the pixels falling within the range of 40.00 to 110.00 g/m\({}^{2}\). Similarly, the total carbon sequestration by corn ranged from 45.15 to 639.57 g/m\({}^{2}\), with 98.24% of the pixels having values between 150 and 500 g/m\({}^{2}\). Conceptualization, G.Y. ; methodology, G.Y. and Z.Z. ; validation, H.S. ; formal analysis, L.H. ; investigation, Z.Z., Y.S. and L.H.