## 4 Discussion  
The fragmentation of cultivated land is one of the main factors restricting agricultural scale operation, and it is a common phenomenon in many countries and regions, especially in Central and Eastern Europe, India, and China [27; 71; 72; 73; 74; 75]. Previous studies were mostly based on sample survey data and field interview data from specific times and areas [13], which have drawbacks that include small coverage, small sample size, and limited representativeness. Based on the interpretation of remote sensing images, this paper uses landscape metric methods to reveal the spatiotemporal evolution characteristics of agricultural land \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Year**} & **Number of Family Farms** & **The Number of Farms** & **The Number of Farms** & **The Number of Farms** \\  & **Family Farms** & **with Less Than 6.67 ha** & **Farms with 6.67–10 ha** & **with More Than 10 ha** \\  & **of Arabic Land** & **of Arabic Land** & **of Arabic Land** & **of Arabic Land** \\ \hline
2013 & 1893 & 784 & 747 & 362 & 4914 \\
2014 & 3067 & 964 & 1356 & 747 & 8105 \\
2015 & 3829 & 997 & 1833 & 999 & 10,005 \\
2016 & 4243 & 810 & 2191 & 1242 & 10,604 \\
2017 & 4516 & 800 & 2219 & 1497 & 11,351 \\
2018 & 4434 & 650 & 2192 & 1592 & 10,771 \\
2019 & 4347 & 619 & 2088 & 1640 & 10,731 \\ \hline \hline \end{tabular}
\end{table} 
Table 16: Statistics on family farms in the suburbs of Shanghai. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Year**} & **Number of Specialized** & **Total Number of** & **Drive the Number of** \\  & **Farmer Cooperatives** & **Members** & **Nonmember Farmers** \\ \hline
2013 & 3200 & 69,578 & 106,322 \\
2014 & 3192 & 68,164 & 122,169 \\
2015 & 3216 & 64,561 & 122,809 \\
2016 & 3202 & 64,421 & 122,848 \\
2017 & 2813 & 62,966 & 144,200 \\
2018 & 2865 & 62,686 & 146,393 \\
2019 & 2757 & 58,662 & 133,888 \\ \hline \hline \end{tabular}
\end{table} 
Table 15: Development of specialized farmer cooperatives in the suburbs of Shanghai. in the suburbs of Shanghai. The research perspectives are more diverse and the study duration is longer. In fact, farmland fragmentation can be divided into natural fragmentation, property rights fragmentation, and agricultural business activities fragmentation or non-agricultural business activities fragmentation. Although natural fragmentation is inevitable, the fragmentation of property rights and human activities can be ameliorated or exacerbated to some extent. Since Shanghai implemented the policy of Pudong development and opening up in 1990, the rapid development of industrialization and urbanization in Shanghai has led to a sharp reduction in the area of agricultural land [24; 76]. First, due to the continuous occupation of cultivated land by urban construction, rural residential construction, rural road and other infrastructure construction, and non-agricultural industrial development, the total amount of cultivated land in Shanghai continue to decrease from 323,200 ha in 1990 to 158,900 ha in 2019. However, in recent years, due to the rapid reduction of rural population and the strengthening of cultivated land protection, the area of cultivated land owned by each rural population or rural employee has increased (Table 17). Second, in terms of space, Shanghai has flat terrain, high intensity of land development and high spatial suitability. The layout of cultivated land is adjacent to the development of construction land. In addition, the road network and water network are too dense, and the distribution of cultivated land by the roads, houses, and rivers is scattered and fragmented. Agricultural land has been increasingly broken up by various types of non-agricultural land, resulting in the decrease of concentrated and contiguous agricultural land. Based on this kind of change situation, the Shanghai municipal government proposed the development strategy of the \"Three Concentrations\" in 1995.