Spatiotemporal Changes and the Driving Forces of Sloping Farmland Areas in the Sichuan Region

Abstract

Sloping farmland is an essential type of the farmland resource in China. In the Sichuan province, livelihood security and social development are particularly sensitive to changes in the sloping farmland, due to the region's large portion of hilly territory and its over-dense population. In this study, we focused on spatiotemporal change of the sloping farmland and its driving forces in the Sichuan province. Sloping farmland areas were extracted from geographic data from digital elevation model (DEM) and land use maps, and the driving forces of the spatiotemporal change were analyzed using a principal component analysis (PCA). The results indicated that, from 2000 to 2015, sloping farmland decreased by 3263 km 2 in the Sichuan province. The area of gently sloping farmland (<10 • ) decreased dramatically by 1467 km 2 , especially in the capital city, Chengdu, and its surrounding areas. However, the steep sloping farmland (>25 • ) decreased by 302 km 2 , and was still the largest portion of total farmland in the area. The PCA analysis indicated that the main driving forces behind the changes were social and economic factors. The influence of agricultural intensification factors, such as the multiple cropping index and sown areas of crops, was relatively weak. Given the decrease in the overall slope cultivated area and the increased portion of moderately steep slope land (10-25 • ) in the cultivated area, special attention should be paid to the scientific conservation of sloping farmland during rapid social and economic development.Sustainability 2019, 11, 906 2 of 16 has significantly decreased because of degradation and the conversion of farmland into building land [17,18], where the increasing speeds of construction and forest land are faster than other land use types [19].Slope cropland is an ecosystem involving the interaction of both natural and social factors [20][21][22]. The evolution of the sloping farmland system has not only been influenced by natural conditions, but also by social and economic factors [23,24]. The decrease in human-induced cultivated land has become a serious problem, particularly with the increasing global population growth and the unreasonable utilization of water and soil resources by human beings [25][26][27][28]. Humans' social and economic activities have played a decisive role in changing cultivated land, where the impact of socio-economic and related industrial policies has been felt over a short period of time, including population growth, agricultural structure adjustment, urbanization, GDP per capita, output value, etc. [29,30]. Nowak and Scheifder found that sloping farmland was seriously affected by agricultural activities, and that the degradation areas were mainly located at the agriculturally intensive areas [31]. The International Geosphere-Biosphere Programme (IGBP) and the International Human Dimensions Program on Global Environmental Change (IHDP) have identified the main driving forces of land-use and land-cover, which are natural environments, land-use management, a...

Exploring cultivated land evolution in mountainous areas of Southwest China, an empirical study of developments since the 1980s

“…Expressly, changes in cultivated land in mountain areas are directly limited by local natural conditions and are also greatly affected by socioeconomic modes, policy implementation, and farmers' livelihoods (Li, Zinda, & Zhang, 2019). For instance, due to different interest objectives of policy implementation departments, social, economic, and agricultural intensification factors have significant differences on the impact of cultivated land undertaken on slopes at a prefecture‐level city in Sichuan Province (Xiao et al, 2019); 66.20% of the differences in cultivated land change drivers of Chongqing come from the district/county level (Song, Cao, Zhou, Su, & Qiu, 2020). Ultimately, human disturbance in terms of management has the most significant impact on the evolution of cultivated land (Liang, Li, & Zhou, 2020).…”

The Impact of Climate Change and Human Activity on Spatiotemporal Patterns of Multiple Cropping Index in South West China

“…The areas of steep slope farmland (>25 • ) decreased by 302 km 2 , still accounting for the largest proportion of cultivated land area throughout the region. Terrain changes were the main cause of the reductions in the MCI in this region [55]. Furthermore, correlation analysis showed that there was a significant decreasing exponential relationship between the relief amplitude and MCI in the three provinces (y = 326.77e −0.01x , R 2 = 0.3336, P < 0.01), which further proved that the MCI decreased as the relief amplitude increased.…”

Prediction of Spatiotemporal Changes in Sloping Cropland in the Middle Reaches of the Yangtze River Region under Different Scenarios

“…As the accelerated urbanization has encroached on the cropland in the countryside surrounding cities and towns via construction, large amounts of farmland have been transferred from the south to the north [7], and from urbanizing areas, mostly in plain regions with high soil quality, to the remote rural hinterland with relatively low soil quality [8], that are unlikely to be occupied again by urban expansion and human activities. This continuous land-use transformation is associated with an increasing amount of sloping cropland [9], which is defined as cropland with a slope greater than 2 • [10]. Studies have shown that sloping cropland has become a crucial resource for grain production [10][11][12] and maintaining people's basic livelihoods [13,14].…”

“…This continuous land-use transformation is associated with an increasing amount of sloping cropland [9], which is defined as cropland with a slope greater than 2 • [10]. Studies have shown that sloping cropland has become a crucial resource for grain production [10][11][12] and maintaining people's basic livelihoods [13,14]. It is widely recognized that an increase in the slope gradient results in more surface runoff and soil loss [12,15], causing lower soil fertility and a higher risk of eutrophication in rivers, lakes, and coastal areas [2].…”

“…Regarding the distribution of sloping cropland, studies have focused more on the evaluation of the cultivated layer's soil quality [31], soil and water dynamics [32,33] and soil loss in sloping farmland [12,34,35], ignoring the characteristics of farmland on a vertical-gradient terrain. Only a few studies have shown the spatiotemporal changes in sloping cropland in some provinces of China [10,20], but they simply described the variations in the amounts of cropland at different slopes in the past without predicting them under various development situations. As a result, there is still a paucity of thorough studies on the spatial characteristics of sloping cropland, both in the past and future, especially at relatively large regional scales.…”