Skip to main content
ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Watershed Physical Processes Research » Research » Publications at this Location » Publication #313468
Title: Degradation of soil physicochemical quality by ephemeral gully erosion on sloping cropland of the hilly Loess Plateau, China

Author
item XU, MINGXIAMG - Northwest Agricultural & Forestry University
item LI, QIANG - Northwest Agricultural & Forestry University
item Wilson, Glenn

Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/15/2015
Publication Date: 8/3/2015
Publication URL: http://handle.nal.usda.gov/10113/61235
Citation: Xu, M., Li, Q., Wilson, G.V. 2015. Degradation of soil physicochemical quality by ephemeral gully erosion on sloping cropland of the hilly Loess Plateau, China. Soil & Tillage Research. 155:9-18.

Interpretive Summary: Ephemeral gully erosion (EGE) is a common type of erosion that poses a major threat to the productivity and sustainability of agriculture in many regions. The objective was to evaluate the impact of EGE on physical and chemical soil properties that determine a soil’s quality or health. We proposed that sites with EGE exhibited large changes in soil properties compared with sites outside of the ephemeral gully. This study used a paired sampling method to compare the soil properties at 0-2, 2-5, and 5-10 cm depths at the bottom of ephemeral gullies and immediately outside the gully in croplands of the hilly Loess Plateau. The results showed that EGE posed a threat to the physical and chemical properties of soil and thus reduced soil quality index and that the decrease in the soil quality got progressively worse as the depth of the gully increased. Reductions were observed in soil quality index as stages of EGE (that is the depth of the channel) increased. Two critical EGE stages were defined by 10 cm and 30 cm depths of channels which corresponded with channel depths where the soil quality index decreased significantly. Compared with the soil outside the gully, the 0-2 cm depth of the gully bottom was essentially a net soil deposition layer, especially for the first erosion stage (channel < 10 cm deep). Soil nutrient loss was greatest in the 2-5 cm depth. Soil physical properties were more susceptible and fragile to EGE than soil nutrients. Degradation of soil physical-dominated properties occurred in the first erosion stage, with key factors being soil organic matter, erodibility coefficient and clay content, whereas soil degradation was mainly caused by loss of soil available nutrients during the subsequent erosion stages. This approach of combining field measurements of gullies stages (depth) with laboratory analysis of soil samples may aid in understanding the features of soil degradation as EGE progresses.

Technical Abstract: Ephemeral gully erosion (EGE) is a common type of shallow linear erosion that exerts a major threat to the productivity and sustainability of agricultural systems. The objective was to evaluate the impact of EGE on soil physicochemical properties that determine soil quality. It was hypothesized that sites with EGE exhibit significant changes in soil physiochemical properties compared with sites without EGE. This study used a paired sampling method to compare the soil physiochemical properties of soil at 0-2, 2-5, and 5-10 cm depth of ephemeral gully bottoms to inter-gully areas (CK) in croplands of the hilly Loess Plateau. The results showed that EGE posed a threat to soil physicochemical properties and thus reduced soil quality index progressively as EGE increased. Reductions were observed in soil quality index as stages of EGE (depth of channel) increased. Two critical EGE stages were defined by 10 cm and 30 cm depths of channel where the soil quality index decreased significantly. Compared with the CK, the 0-2 cm depth of the gully bottom was essentially a net soil deposition layer, especially for the first erosion stage (channel < 10 cm deep). Soil nutrient loss was greatest in the 2-5 cm depth. Soil physical properties were more susceptible and fragile to EGE than soil nutrients. Degradation of soil physical-dominated properties occurred in the first erosion stage, with key factors being soil organic matter, erodibility coefficient and clay content, whereas soil degradation was mainly caused by loss of soil available nutrients during the subsequent erosion stages. This approach of combining field ground-truth survey with laboratory analysis to study the in-situ impact of ephemeral gully erosion on soil physicochemical properties may aid in understanding the features of soil degradation caused by EGE.