Effects of Land Use Change of Sloping Farmland on Characteristic of Soil Erosion Resistance in Typical Karst Mountainous Areas of Southwestern China

Abstract

With the implementation of ecological projects such as the Grain-for-Green Project, rocky desertification control and comprehensive control of soil and water loss for sloping farmland, ecological environment of karst mountainous areas in southwest China has been improved significantly, but soil and water loss of sloping farmland is still an important ecological and environmental problem in this region. In this paper we took a typical karst rocky desertification mountainous area, Jinlan Demonstration Area, as the study area located in Qianxi County, Guizhou Province. On the basis of a previous experimental demonstration of grass planting and afforestation on sloping farmland (planted in 2014), the sample plot method was used to obtain soil samples and soil shearing test piece in 2017, and soil shear strength and soil erodibility factor (K) were measured by direct shear method and hydrometer method in order to study the effect of sloping farmland converted to abandoned land, pastureland and agroforestry on soil erosion resistance. Results showed that the soil sheer strength was no obvious change and soil erodibility was no significant difference (P>0.05) in sloping farmland with the level of rocky desertification becoming more serious; soil sheer strength greatly increased after sloping farmland was abandoned, ultimate shear strength τ 300 was increased by 65.5%, and K was significantly different (P<0.05) after 10 years; in the process of sloping farmland converted to pastureland, the soil ultimate shear strength τ 300 was increased by 34.55% and K decreased significantly (P<0.05), which indicated that the effect of grass planting on improving soil erosion resistance of sloping farmland was obvious; in the process of sloping farmland converted to agroforestry, soil erosion resistance was also enhanced, soil shear strength was increased, and K was decreased (it did not reach the significant level, P>0.05). Based on the preliminary results of this paper, we think both grass (tree) planting and land abandonment could improve soil erosion resistance and reduce soil erosion risk, which *

Effect of cropland withdrawal on soil organic carbon in China, 1990–2018

“…In Yunnan province, the average erosion modulus was 12.56 tha −1 a −1 , and more than 77% of areas above the middle erosion level were found in croplands (Duan et al, 2020). However, the conversion of sloping cropland to grassland and wasteland resulted in an increase in soil shear strength by 34.55% and 65.5%, respectively (Li et al, 2019). Besides, Tang et al (2020) predicted that the carbon storage loss caused by cropland reclamation in Hubei province would increase by 3.86 Tg during the period of 2010–2030.…”

“…Second, cropland reclamation in mountainous areas is an uneconomical practice because of the higher labor cost due to the fragmentation of the agricultural landscapes (Figure 9), which makes the large‐scale operation of agricultural machinery difficult and more labor input is required in the process of agricultural production compared to the plain areas (Zhu et al, 2018). For instance, Li and Li (2019) found that the agricultural labor productivity of maize in mountain areas was 2.25 times that in plain areas in 2013. In addition, according to the cost–benefit data of agricultural products, the labor cost of planting an acre of corn in the provinces of Yunnan and Guizhou is 2.24 times the national average in 2019 (National Bureau of Statistics, 2021a).…”

Effects of rainfall, sediment source–sink landscape, and hydrological connectivity on runoff more than sediment in a karst basin

“…Thus, the prevention and control of soil and water loss during the early stages of construction are essential (Que & Zhang, 2021). At the same time, land‐use change has a significant impact on soil resistance to erosion in karst regions (Li, Wu, et al, 2019). Changing the land use from cropland to forest land or grassland, the soil erosion resistance increases (He et al, 2018; Li, Wu, et al, 2019).…”

Riparian Land-Use, Stream Morphology and Streambank Erosion within Grazed Pastures in Southern Iowa, USA: A Catchment-Wide Perspective

“…Knight et al [21] suggested that the addition of a grass zone to the outside of a riparian forest buffer would reduce sediment loss resulting from ephemeral gullies and increase stream water quality. Li et al [22] found an improvement in soil erosion resistance under the planting of grassy vegetation. Other BMPs, such as timing of cattle grazing, non-riparian shade, alternative water sources, and livestock exclusion with fencing, have been shown to effectively increase streambank stabilization [23,24], soil enzyme and microbial activities [25], and stream water integrity [14,26].…”