[Objective] The effects of fish-scale pits at different locations on soil and water conservation were studied in order to define underlying layout principles for fish-scale pits

and to provide information for fish-scale pit site selection and effect evaluation in ecologically fragile areas. [Methods] The study was conducted at Qiansongba in the Bashang grassland area. Plots were established in shady slope

sunny slope

and river valley areas. The effects of fish-scale pits on plant biomass and root system

soil bulk density

and soil nutrient loss were determined. [Results] ① Aboveground biomass

underground biomass

rooting depth

total nitrogen (TN) and dissolved organic carbon were increased for fish-scale pits on the sunny slope

shady slope

and river valley

and the soil bulk density was decreased compared with a control area. ② The effects of fish-scale pits on shady slope

sunny slope

and river valley locations were different. Fish-scale pits on the shady slope and sunny slope significantly increased rooting depth (p<0.05) (104.19% and 42.87%

respectively). Compared with fish-scale pits at the sunny slope

fish scale pits at the shady slope also had significant effects on soil bulk density

TN content

and aboveground biomass (p<0.05) (-9.26%

148.05%

and 136.32%

respectively). Ammonia nitrogen and nitrate nitrogen for the fish-scale pit at the river valley location were significantly higher than for the control group (p<0.05) (125.16% and 174.53%

respectively). ③ Fish-scale pit location and construction time were the most important factors influencing soil and water conservation

rather than slope position. As fish-scale pit construction time increased

aboveground biomass

underground biomass

TN content

and rooting depth increased

and soil redox potential decreased. ④ The effects of fish-scale pits on soil and water conservation in areas with severe soil erosion was more significant than in areas with less erosion. [Conclusion] Fish-scale pits produced significant soil and water conservation effects. The fish-scale pit on the shady slope had more significant soil storage and soil conservation effects than the fish-scale pit on the sunny slope. The fish-scale pit in the river valley had a greater ability to improve soil ammonia and nitrate nitrogen levels than the shady slope and sunny slope pits. Soil and water conservation was enhanced with the increase of construction time of fish-scale pits. In order to improve soil and water conservation effects

fish-scale pits should be built on shady slopes and in river valleys according to local conditions.