Effects of Natural Factors and Production Management on the Soil Quality of Agricultural Greenhouses in the Lhasa River Valley, Tibetan Plateau

Agricultural greenhouses (AGs) are an effective solution to address the growing demand for vegetables despite limited cropland, yet significant soil quality problems often accompany them, particularly in high-altitude regions. However, the effects of natural factors and production management on soil quality are not well understood in such fragile environments. This study analyzed soil quality differences between AGs and adjacent open cropland (OCs) in the Lhasa River Valley, Tibetan Plateau, based on 592 soil samples and 12 key soil physicochemical indicators. GeoDetector was used to identify the dominant factors and their interactions with these differences. The results showed that AG soils had significantly lower pH, with an average decrease of 20%, indicating acidification, while nutrient levels and total salinity were significantly higher compared to OC soils. Specifically, available phosphorus, available potassium, the soil fertility quality index, and total soluble salt increased by 281%, 102%, 38%, and 184%, respectively. Planting, topographic, and fertilizer factors were identified as the dominant factors contributing to these differences. Interaction analysis showed that the interaction of these factors increased the explanatory power by 20.2% to 41.32% compared to individual factors. The interaction between planting year and fertilizer type had the highest explanatory power for nutrient increases and pH decline, while fertilizer amount and slope aspect contributed to salinity accumulation. These findings provide valuable insights and practical guidance for optimizing AG management and ensuring sustainable agricultural development in high-altitude regions.