# Analysis of Cultivated Land Productivity in Southern China: Stability and Drivers
## 4 Discussion  
### Cultivated Land NPP Stability: A Core Indicator of System Resilience  
Environmental stressors, such as climate change, drought, and wildfires, can decrease NPP; therefore, NPP serves as an important index for evaluating the response of cultivated land systems to disturbance stability [40]. Our analysis of NPP during 2001-2022 revealed that the stability of cultivated land productivity increased, with significant mutation points. The Mann-Kendall mutation point method identified 2010 as a key change point when NPP shifted from decline to growth (Figure 10). This trend, characterized by an initial decrease followed by recovery, reflects the resilience of the cultivated land system to external interference [41]. This shift may be associated with flooding in the Yangtze River Basin in 2010, including the Poyang Lake region, following continuous heavy rainfall. In-depth analyses of mutation points in NPP, temperature, and precipitation revealed that fluctuations in NPP were associated with precipitation change rates. This indicated the significant correlation between the stability of cultivated land productivity and extreme weather events, particularly precipitation conditions. However, this finding contradicts previous research on the response of NPP to climate factors in the Yangtze River Economic Belt [42], where the sensitivity of NPP to temperature changes did not exceed its sensitivity to precipitation. This is likely because precipitation changes were more dramatic in the \begin{table}
\begin{tabular}{l c c c c c} \hline \hline  & **Non-Standardized** & \multicolumn{2}{c}{**Standardization Coefficient**} & \multicolumn{2}{c}{**Significance**} & \multicolumn{2}{c}{**Collinearity Statistics**} \\ \hline  & **B** & **Beta** & & **Tolerance** & **VIF** \\ \hline Constant & \(-811.789\) & & 0 & & \\ _Field_road_ & \(-0.01\) & \(-0.183\) & 0.071 & 0.551 & 1.816 \\ _distance_ & \(0.02\) & \(0.691\) & 0 & 0.62 & 1.612 \\ _AREA_MN_ & \(1.66\times 10^{-6}\) & \(0.218\) & \(0.018\) & \(0.725\) & 1.379 \\ _FRACT_ & \(793.149\) & \(0.481\) & 0 & 0.451 & 2.219 \\ _ENN_ & \(-0.246\) & \(-0.706\) & \(0.001\) & 0.18 & 5.558 \\ _MAT_ & \(0.324\) & \(0.077\) & \(0.734\) & \(0.101\) & 9.93 \\ _MAP_ & \(-0.006\) & \(-0.371\) & \(0.037\) & \(0.186\) & 5.384 \\ \hline \hline \end{tabular} R\({}^{2}\): 0.915, [PERSON]: 2.318.  
\end{table} 
Table 1: Multiple linear regression model coefficients. study area than temperature changes, leading to a higher sensitivity of NPP to precipitation variations [43; 44]. The resilience of the cultivated land system is evident in several aspects: (1) resistance, including anti-interference capabilities, such as climate change and soil erosion; (2) the buffer resistance effect, which ensures that the entire ecosystem can adapt to environmental changes and function regularly; and (3) productivity, a key function to ensure crop growth and food production [45]. Cultivated land ecosystems are affected not only by crop growth stability and land productivity but also by the complex interactions between farmland and the external environment [46]. These characteristics emphasize the importance of cultivated land resilience in the face of external pressures and change. Therefore, when considering  
Figure 10: Mann–Kendall mutation point tests for NPP, precipitation, and temperature. the stability of cultivated land productivity, the resilience of cultivated land systems must be considered to maintain productivity and resist external environmental changes [47]. Achieving this requires an in-depth analysis from the perspectives of spatial layout and farmland infrastructure [48]. Field and river proximities affect irrigation conditions, thereby impacting crop yield. Good irrigation can help achieve crop yields and improve farmers' income [49]. The anti-waterlogging effect of irrigation and water conservancy projects is obvious in humid areas, such as Fujian, Jiangxi, and Hubei [50].