*4.2. The Regional Difference of the Study Area in Land-Use Transition*

Analysis of regional differences is important to understand the dynamics of agricultural land use in each region. We have firstly analyzed the cropland and grassland. Concerning cropland, from 2009 to 2018, an increase is noted in all the five regions. The region of Kaffrine has the highest value with 1337.95 km2 (22.80%). It is followed by the regions of Diourbel (19.50%) and Fatick (9.71%). The regions of Kaolack and Thiès show 3.83% and 2.53% over the ten years, respectively. This increase hides inter-annual disparities. Between 2009 and 2012, the area of cropland in the Diourbel region decreased by −5.81%. However, over the same period, the area increased in Fatick (4.27%), Kaffrine (13.31%), Kaolack (7.01%), and Thies (1.70%). This approach shows that cropland evolution is not exponential but in a sawtooth pattern. This pattern is similar to grassland. In general, it has decreased. The Kaffrine region occupied first place with −24.81%, followed by the Diourbel (−18.74%) and Kaolack (−7.26%). In contrast, the Thiès region shows an increase of 0.11%.

For urban and built-up and permanent wetland, the situation is the same. Concerning urban and built-up, the region of Thies comes in first place with an evolution of 4.02 km2 (7.94%) between 2009 and 2018 (Figure 3). This evolution trend remains the same for the Diourbel region with 0.93%. The evolution of urban and built-up is average in the Factick region with 0.77%. In contrast, the regions of Kaolack (−0.17%) and Kaffrine (−0.61%) show a decrease in urban and built-up areas in the same period. Permanent wetland concern largely the Fatick and Thiès regions. In the Thiès region, the evolution is stable. However, in the region of Fatick, it has been recorded an increase of 9.80 km<sup>2</sup> (1.31%). However, this result hides disparities. In the same region shows an increase of 2.60% from 2009–2012, to reach a decline of −1.43% from 2015–2018. Finally, the analysis of regional differences in land use shows several aspects. The first aspect shows that in the regions of Kaffrine and Diourbel, cropland has evolved rapidly, but urban and built-up remains low in Kaffrine (Figure 3). In contrast, urban and built-up expansion is relatively rapid in the Thiès region, and moderate in the Diourbel region. However, in the Thies region, the evolution of cropland and grassland has evolved weaknesses compared with other regions.

**Figure 3.** Regional differences in land use evolution from 2009 to 2018 (%).
