Characteristics of Soil Nitrogen and Phosphorus in Different Types of Areas in the Pisha Sandstone Region

Abstract Little is known about the distribution of N and P in Pisha sandstone soils from different types of areas. In this study, three typical areas in this region, which included the Er Laohu small watershed (soil-covered area), the Tela small watershed (sand-covered area), and the Shibu Ertai small watershed (bare area), were chosen as experimental objects. A total of 27 soil sections were constructed (Took three parts in the upper, middle and lower of each watershed, respectively), and 486 soil samples were taken from different slope positions and slope directions. Bare Pisha sandstone had the highest mean TN concentration of 0.53 g/kg, which was about 45.06–45.30% higher than soil-covered and sand-covered Pisha sandstone. Sand-covered Pisha sandstone had a lower TP concentration of 37.93–40.62% than the bare (5.04 g/kg) and soil-covered (4.64 g/kg) Pisha sandstone. The concentration of AN in the bare Pisha sandstone was 23.98 mg/kg, which was about 2.85-3.85 times higher than that in the sand-covered and soil-covered Pisha sandstone. Ni concentration in bare Pisha sandstone (5.14 mg/kg) was approximately 3–4 times higher compared to soil-covered and sand-covered Pisha sandstone. The AP concentration in soil-covered Pisha sandstone was 7.56 mg/kg, which was about 68–72.21% higher than that in bare and sand-covered Pisha sandstone areas. Overarchingly, our results suggest that different Pisha sandstone types and slope positions significantly affect the spatial distribution of N and P. That has created a greater obstacle for the local population to carry out agricultural activities in the Pisha sandstone region.