Correlation analyses among terrains diversity, soil types diversity, and dynamic change in arable land

Soil diversity research has been a major focus of the soil science research community since the start of the 21st century. In recent years, some scholars have initiated research on diversity in land resources, water bodies, topographies, and parent materials, which has broadened the field of diversity studies. The exploration of the diversity in arable land is limited. This study focuses on the use of spatial data information to explore the regional diversity and differences of various geo-elements in arable land. Three typical research areas in northern, central, and southern regions of Henan Province, respectively, were selected to calculate the dynamic change (2001, 2007, and 2017) in arable land over time based on the topographic and soil conditions at the scale of 1 km×1 km, 3 km×3 km, and 5 km×5 km grids. And the correlation index was determined using the ArcGIS and SPSS softwares in combination with the correlation analysis method. The purpose of this analysis was to provide a new research perspective on the driving force of the dynamic change in arable land resources and guide their future rational use. The results showed that, first, the diversity of topographic components in the northern and central Henan regions was similar, whereas that in the southern Henan region was relatively unvarying. The terrain's spatial distribution diversity of each study area was plain > hill > mountain. Second, the soil composition in the southern Henan region was the most homogeneous and abundant, and it was relatively uniform in central Henan. The typical soil was different in each study area, but its distribution was uniform overall. Third, an important factor influencing the diversity of terrain and soil spatial distribution is at what scale it is measured, and the 3 km×3 km grid was suggested as the most suitable research scale. Fourth, the spatial distribution diversity index of the soil and terrain containing arable land changed the area spatial distribution and had obvious relevance. Among the three regions, the plains in the topography had a high correlation of approximately 0.95. In addition, the correlation between the typical soil (such as paddy soil in southern Henan, cinnamon soil in southern and northern Henan, and fluvo-aquic soil in northern Henan) and difference in the arable land within each study area was more discernable, reaching over 0.9. Overall, the compositional diversity and spatial distribution pattern of the topography and soil factors were significantly different in the representative study areas. Using a different grid scale, the difference in the arable land area is closely related to the spatial distribution diversity index of the topography and soil factors.