Improving water retention capacity of an aeolian sandy soil with feldspathic sandstone

Lu Zhang,Jichang Han

doi:10.1038/s41598-019-51257-y

Abstract

The Mu Us sandy land in China’s Shaanxi Province faces a critical water shortage, with its aeolian sandy soil endangering the regional eco-environment. Here we investigated the effects of feldspathic sandstone on water retention in an aeolian sandy soil from the Mu Us sandy land. Feldspathic sandstone and aeolian sandy soil samples were mixed at different mass ratios of 0:1 (control), 1:5 (T1), 1:2 (T2), and 1:1 (T3). Soil-water characteristic curves were determined over low- to medium-suction (1–1000 kPa) and high-suction (1000–140 000 kPa) ranges, by centrifuge and water vapor equilibrium methods, respectively. Results showed that the addition of feldspathic sandstone modified the loose structure of the aeolian sandy soil mainly consisting of sand grains. The van Genuchten model described well the soil-water characteristic curves of all four experimental soils (R2-values > 0.97). Soil water content by treatment was ranked as T2 > T3 > T1 > control at the same low matric suction (1–5 kPa), but this shifted to T2 > T1 > T3 > control at the same medium- to high-suction (5–140 000 kPa). T2 soil had the largest saturated water content, with a relatively high water supply capacity. This soil (T2) also had the largest field capacity, total available water content, and permanent wilting coefficient, which were respectively 17.82%, 11.64%, and 23.11% higher than those of the control (P-values < 0.05). In conclusion, adding the feldspathic sandstone in an appropriate proportion (e.g., 33%) can considerably improve the water retention capacity of aeolian sandy soil in the study area.

Highlights

Soil water shortage is often a key factor that limits crop production and agricultural development in desert
After the addition of feldspathic sandstone to the aeolian sandy soil, the frequency distribution curves of T1 to T3 soils could be divided into two parts, with the grain size of 0.05 mm as the boundary
When grain size 0.05 mm, the content of coarse-sized grains gradually decreased with increasing addition of feldspathic sandstone

Summary

Introduction

Soil water shortage is often a key factor that limits crop production and agricultural development in desert. After the Yellow River channel was basically formed (100 000 to 10 000 years ago), a river paleolake formed a tableland via the alluvial and alluvial effects of flowing water; aeolian activity since the middle and late Quaternary created the present geomorphologic landscape of this sandy land[17] In this region, feldspathic sandstone occurs across a wide area of ~16 700 km[2]. The abundant secondary clay minerals contained in feldspathic sandstone provide a rare yet ideal material for “water retention” in sandy lands[20,21,22] These features point to a new idea for how to compensate for the poor water properties of aeolian sandy soil using feldspathic sandstone. The van Genuchten model has a wider range of application and is broadly used to the fit the data obtained from soils differing in their properties[30,31,32,33,34,35,36]

Methods

Results

Discussion

Conclusion