Transformation of Paddy Field Use in Intermountain-Type Basins Using Evidence from the Structure and Function Perspective of Karst Mountain Areas in Southwest China

Abstract

China’s southwestern karst area exhibits many mountains and little flat lands, and intermountain basins (IBs) (locally named “bazi”) are one of their typical landform types. Comparative studies on land use in the core of typical landforms in karst mountain areas are relatively lacking. Studying the evolution and transformation patterns of intermountain basin paddy fields use (IBPFU) to optimize land resources in mountainous areas is important. Based on structural and functional perspectives, this study established a research framework on the evolution and transformation of IBPFU in karst mountainous areas, and analyzed the evolution and transformation patterns of IBPFU in Guizhou Province from 1966 to 2020 by measuring land use change and applying the moving window method and morphological spatial pattern analysis (MSPA) model. The study showed that the evolution of IBPFU is characterized by reversibility and irreversibility, diversity, and stages. The transition of IBPFU requires a trade-off among regional socioeconomic development, ecological protection, and food security. The commonality of land use transitions in IB and sloped land (SL) is reflected in the diversity of their land use functions. This study provides a reference for a comprehensive understanding of land use transitions and sustainable development in the mountainous karst regions of southwest China by providing in-depth examinations of the land use transition of IB, which is different from SL, via the long time series evolution of core land use types. The research framework and research method constructed here also apply to other regions.

Evolution and Transformation Analysis of Land-use in Mountainous “Granary”—Evidence from Typical Basin in Karst Mountainous Areas of Southwest China

“…The basin has long been planted mainly with traditional crops, such as rice, and is one of the important "granary" bases in Guizhou Province. However, in recent years, due to the low economic income from traditional food crops, most of the traditional agricultural cultivation in the basin has gradually shifted to modern agriculture, such as greenhouse vegetables, fruit bases, and the flower and seedling industry, resulting in significant changes of land-use in the basin [31].…”

“…Therefore, how to rationally allocate arable land resources according to the many functions of arable land, to meet the diversified needs of human society for the products and services formed on arable land is the difficulty, and is a hotspot in current arable land protection work [34]. Based on existing studies [31], the authors argue that, during the evolution of the land-use in the basin, the general trend is that the arable land-use function gradually decreases while other functions gradually increase, or although the arable land-use function is still the main feature, the diversity of arable land function continues to increase. Suppose the evolution of the basin's land-use function is inconsistent with this general trend.…”

“…Modern agricultural land refers to facility agricultural land with a larger area and scale, such as greenhouse vegetable bases, flower bases, and economic fruit planting bases, with higher land-use intensification and efficiency. Combining the actual conditions of the study area and according to the current land-use classification promulgated in 2017 [37], we divided the second-class land-use status in the Lianjiang Basin area into 30 categories: paddy field (11), dry land (13), forested land (31), Regarding the ground data of the same period, some sample areas were randomly selected, and through several field investigations, the classification confusion matrix was statistically obtained, and the Kappa index was calculated to test the accuracy of the landuse data in each period. The results showed that the Kappa indices for 1966, 1973,1990,2006,2010,2016, and 2020 were 0.81, 0.80, 0.83, 0.90, 0.85, 0.91, 0.93, respectively, and that the results met the minimum allowable discrimination accuracy of 0.70 [36].…”

“…Modern agricultural land refers to facility agricultural land with a larger area and scale, such as greenhouse vegetable bases, flower bases, and economic fruit planting bases, with higher land-use intensification and efficiency. Combining the actual conditions of the study area and according to the current land-use classification promulgated in 2017 [37], we divided the second-class land-use status in the Lianjiang Basin area into 30 categories: paddy field (11), dry land (13), forested land (31), shrub land (32), natural grassland (41), industrial land ( 61 company contracted open-air vegetable base (12023), greenhouse strawberry planting base (12031), grape planting base (12032), dragon fruit planting base (12033), blueberry planting base (12034), greenhouse watermelon planting base (12035), economic fruit planting base (peach and plum) (12036) landscape ecological holiday leisure area (12041), and fish pond facility (12051) (Figure 3). The resolution of the remote sensing images in the study area at seven time periods was not consistent, so the authors conducted several field surveys for modification and validation, and the accuracy of the data reached more than 90%; on the other hand, the obvious changes in land-use in the study area occurred after 2000, so the difference in the resolution of the remote sensing images at seven time periods will not affect the results of this paper.…”

“…Answering these questions is very urgent at present. Existing studies on the basin in karst mountainous areas focus on mountain-basin land-use coupling [29], the evolution of basin land-use functions [30], transformation of paddy land-use in intermountain basins [31] and differences in urban patterns in intermountain basins [27,32]. However, there is still a lack of in-depth research, based on typical cases, on the changing law of land-use transition in rural basins over a longer period of time and at multiple spatial scales.…”