## 4 Discussion  
Currently, no unified standard exists for the definition of abandoned farmland, both in domestic and international research. A review of relevant literature reveals that definitions such as \"farmland left idle for one season or more\", \"farmland left idle for more than one year\", and \"farmland left idle for two or more years without cultivation\" are commonly used [65, 66]. Qiaotou Town, located in a tropical region, experiences a summer-like climate year-round, making it suitable for crop cultivation throughout the year. The area is renowned for its sweet potato production, with the planting season spanning from October to March of the following year. During this period, cultivated land is rarely left fallow. Therefore, if cultivated land is detected without crop cultivation during this time, it can be classified as abandoned. Abandoned farmland typically exhibits minimal long-term vegetation cover changes, whereas cultivated land with spontaneous vegetation. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Feature** & **Range** & \begin{tabular}{c} **Farmland** \\ **Area/hm2** \\ \end{tabular} & \
\begin{tabular}{c} **Abandonment** \\ **Area/hm2** \\ \end{tabular} &
\begin{tabular}{c} **Abandonment** \\ **Rate/\%** \\ \end{tabular} \\ \hline \multirow{4}{*}{Slope} & 0–2\({}^{\circ}\) & 995.08 & 23.61 & 2.37 \\  & 2–5\({}^{\circ}\) & 2177.63 & 54.14 & 2.49 \\  & 5–10\({}^{\circ}\) & 660.34 & 5.44 & 0.82 \\  & 10–15\({}^{\circ}\) & 17.47 & 0.12 & 0.67 \\  & \textgreater{}15\({}^{\circ}\) & 7.56 & 0.18 & 2.38 \\ \hline \multirow{4}{*}{Distance to water system} & \textless{}100 m & 358.79 & 4.73 & 1.32 \\  & 100–300 m & 527.50 & 12.88 & 2.44 \\  & 300–500 m & 421.63 & 19.88 & 4.71 \\  & 500–700 m & 434.27 & 20.49 & 4.72 \\  & \textgreater{}700 m & 2115.79 & 25.52 & 1.21 \\ \hline \multirow{4}{*}{Distance to road} & \textless{}50 m & 1003.01 & 33.80 & 3.37 \\  & 50–100 m & 900.38 & 23.64 & 2.63 \\  & 100–150 m & 686.34 & 11.31 & 1.65 \\  & 150–200 m & 475.45 & 7.88 & 1.66 \\  & \textgreater{}200 m & 792.80 & 6.86 & 0.86 \\ \hline \multirow{4}{*}{Distance to residential area} & \textless{}100 m & 948.73 & 19.10 & 2.01 \\  & 100–300 m & 1952.05 & 26.60 & 1.36 \\ \cline{1-1}  & 300–500 m & 809.39 & 25.70 & 3.18 \\ \cline{1-1}  & 500–700 m & 135.08 & 8.93 & 6.61 \\ \cline{1-1}  & \textgreater{}700 m & 12.72 & 3.16 & 24.87 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Farmland area and abandonment rate in different ranges for different features. Figure 9: Spatial distribution of abandoned farmland around residential areas. as well as the ratio of cultivated land area and abandonment rate within the buffer zone. (**a**) Perennial abandonment of farmland. (**b**) Seasonal abandonment of farmland. (**c**) Cultivated land ratio and abandonment rate. tion may show seasonal variations. By conducting change detection using images from two different periods and analyzing spectral characteristics, the two can be effectively distinguished. During the sample selection process, we excluded cultivated land samples potentially covered by spontaneous vegetation to reduce classification errors. The high spatial resolution of satellite imagery significantly enhances the accuracy of the results. In this study, high-resolution satellite imagery was employed to identify abandoned farmland in tropical regions, yielding high overall accuracy and a strong Kappa coefficient for the extraction results. During specific phases of rural economic development, the phenomenon of abandoned farmland is inevitable [67]. The relationship between the driving factors of abandonment and their regional distribution is variable over time and space [68]. Understanding the factors influencing land abandonment is crucial for developing reclamation policies and ensuring agricultural sustainability.