Soil quality assessment of cropland in China and its relationships with climate and topography

Abstract

Assessing soil quality (SQ) of cropland is fundamental for food security and sustainable land management. However, there is limited information regarding SQ assessment on a national scale, which is vital to answer important SQ-related questions in quantitative terms on that scale. Here, the SQ of cropland in China was assessed by constructing a minimum data set (MDS) from 23 soil physicochemical properties based on principal component analysis. The interaction roles and relative contributions of climate and topography on SQ was evaluated by a structural equation model.The MDS comprised eight indicators: proportion of silt, bulk density, total phosphorus, total potassium, available nitrogen, exchangeable calcium, chlorite, and vermiculite. The soil quality index (SQI) varied from 0.245 to 0.705 and showed a clear pattern of decreasing quality from the north to the south of the country. Of the total cropland area in China, the largest share (27.91%) was of soils of high quality, followed by those of moderate quality (24.63%), low quality (20.37%), very high quality (14.18%), and very low quality (12.91%). The north and the south differed significantly in terms of total potassium, exchangeable calcium, chlorite, and vermiculite, which are the four most important indicators of SQ. Climate and elevation explained about 2.2%-30.1% of the variation in SQ on the national and regional scales. These findings suggest that croplands in southern China will benefit from potassium and calcium fertilizers, which will contribute to enhance food security and promote sustainable land management in China.

A novel framework to integrate cropland quantity and quality from pixel to county level: Implications for requisition–compensation balance of farmland policy in China

“…The cropland quality that ranged from 0.2 to 0.4 had the largest area proportion (51.47%), followed by cropland quality between 0.4 and 0.6 (27.74%). These results showed good agreement with the previous study by Li et al (2022), which indicated the regions in the middle and lower reaches of the Yangtze River were dominated by low‐level soil quality. The lowest cropland quality (<0.2) is mainly concentrated in the western regions where the mountainous terrains adversely impacted farming activities.…”

Assessing and mapping cropland abandonment risk in China

“…Previous studies have shown that slopes and topographic relief increase the difficulty and cost of farming, as they require more labor, machinery, and inputs (Tarolli & Straffelini, 2020; He et al, 2020). They also affect cropland's soil quality and productivity, making it less attractive and viable for farming (Li et al, 2023). In addition, the terrain limits the construction and maintenance of transportation and irrigation facilities, which influences the accessibility and connectivity of cropland (Wang, Li, et al, 2020; Liu et al, 2019; Li et al, 2023), further restricting agricultural productivity (Liu, Song, et al, 2019; Wang, Li, et al, 2020), and creating barriers and isolation for farmers and markets (de Bruin et al, 2021; Xu et al, 2020).…”

“…They also affect cropland's soil quality and productivity, making it less attractive and viable for farming (Li et al, 2023). In addition, the terrain limits the construction and maintenance of transportation and irrigation facilities, which influences the accessibility and connectivity of cropland (Wang, Li, et al, 2020; Liu et al, 2019; Li et al, 2023), further restricting agricultural productivity (Liu, Song, et al, 2019; Wang, Li, et al, 2020), and creating barriers and isolation for farmers and markets (de Bruin et al, 2021; Xu et al, 2020). Western China covers a large area with low population density and low level of economic development, farmers in western China tend to abandon their cropland and go out to find more profitable opportunities (He et al, 2020; Zang et al, 2020; Ma et al, 2022).…”