The researchers studied how soil water content varies in a desert grassland in China after introducing a shrub called Caragana korshinskii. They used statistical and geostatistical methods along with GIS data to analyze the soil water content in different layers. They found that the soil water content was relatively low and varied across the soil layers. The introduction of the shrub has led to depletion of soil water, especially in the deep layers, causing spatial heterogeneity and fragmentation of soil water. This means that the soil water is not evenly distributed, with stronger effects in the deeper soil layers.