## 3 Results  
### Overall Characteristics of Cropland Use Transition in Guangdong Province  
From 1991 to 2020, the total area of cropland in Guangdong Province showed a decreasing trend, which was opposite to the trend of the cropland use transition rate (Figure 4). Specifically, during the study period, the total cropland area decreased by 9.85 thousand km\({}^{2}\), a decrease of about 35%. The reduction in cropland area occurred in three distinct phases: 1992-1994, 1998-2000, and 2004-2016. During the first phase, the cropland area decreased by 8.42 thousand km\({}^{2}\), while the cropland use transition rate increased by 4.31%. This phase saw the highest loss of cropland due to abandonment and non-agricultural use in nearly 30 years, averaging an annual loss of 8.74 thousand km\({}^{2}\). The cropland use transition rate continued to decrease after 1994, reaching its low  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Status** & **Serious** & **Less Balanced** & **Basic** & **Perfect Balance** \\  & **Imbalance** & & **Equilibrium** & \\ \hline BV (10\({}^{4}\)t) & \(-10\)\(<\) & \(-10\)\(\mathrm{\text{---}}1\) & \(-1\)\(\mathrm{\text{--}}1\) & \(>\)1 \\ \hline \end{tabular}
\end{table}
Table 2: Categorization.  
est point of 20.18% in 2001. During the second phase, the cropland area decreased by 4.52 thousand km\({}^{2}\), with only 1.32 thousand km\({}^{2}\) lost to abandonment in 1999. The period from 2004 to 2016 marked the longest continuous decline in cropland area. Economic development triggered a new wave of urbanization, resulting in a total reduction of cropland area by 10.4 thousand km\({}^{2}\). Meanwhile, the cropland use transition rate rose rapidly, reaching its maximum in the study period in 2013 at 34.14%, highlighting the intensity of the cropland use transition. Additionally, from the spatial distribution of the cropland use transition (Figure 5c), the most frequent occurrence of cropland use transition was in Zhanjiang and Maoming in WG, as well as Jieyang in EG, where the cropland use transition rate in many areas exceeded 60%. The PRD region followed, with an overall cropland use transition rate of 20-40%, and the region with the smallest cropland use transition changes was NG. Overall, the annual average loss of cropland area due to non-agriculturalization and abandonment was 2.76 thousand km\({}^{2}\) and 3.09 thousand km\({}^{2}\), respectively, while the annual average replenishment of cropland area was 2.94 thousand km\({}^{2}\).  
Based on the distribution map of cropland and population gravity centers (Figure 5a,b,d), it's clear that their gravity centers shifted in opposite directions. The longitude and latitude changes show negative correlations of \(-0.9\) and \(-0.79\), indicating more pronounced changes in longitude. Specifically, from 1991 to 2020, the cropland gravity center shifted northwestward by 21.2 km at a rate of 0.71 km/a, moving 20.18 km westward and 6.52 km northward. The study also finds that the center of gravity of cropland is shifting toward the northwest hilly area. This may lead to a decrease in the soil fertility of newly added cropland, thus affecting food production. Meanwhile, the population gravity center shifted southeastward by 11.35 km at a rate of 0.38 km/a, moving 9.22 km eastward and 6.62 km southward. The population center of gravity has further shifted to the economically developed coastal areas. This indicates an intensifying decoupling between cropland and population distribution in Guangdong province.  
Figure 4: Temporal variation characteristics of cropland use transition area in Guangdong province from 1991 to 2020.