Effect of Soil Configuration on Alfalfa Growth under Drought Stress

Abstract

This paper aims to compare the effect of different soil configurations on plant growth under long-term drought to provide a theoretical basis for soil reclamation and vegetation restoration in the contiguous area between Shanxi, Shaanxi, and Inner Mongolia, China. With the widely distributed montmorillonite-enriched sandstone in this area as the soil structure ameliorator and the sandy soil as the test soil, indoor simulation and soil column tests were conducted to study the water holding capabilities of different reconstructed soils configurations. The drought stress test of alfalfa on these soils explored the correlation between the growth of alfalfa and soil water in various configurations. The soil–water characteristic curve and soil texture were analyzed to determine plant survival. The results showed that the addition of montmorillonite-enriched sandstone with high water holding capacity and water diffusion rates could increase the water content of the sandy soil. The treatments with 20 and 30 cm montmorillonite-enriched sandstone at the depths of 20–40 cm and 20–50 cm demonstrated the longest survival time (60 days and 59 days), the highest germination (34% and 35%), and the highest water holding capacity (22.6% and 27.3%), indicating that soils with higher water holding capacity and lower diffusion rates could be used as a reservoir, in combination with other soil materials with high water content, and that the addition of the montmorillonite-enriched sandstone layer at 20–30 cm in the sandy soil is the optimal choice for topsoil reclamation in open-mining areas.