The bedrock dip angle is a critical factor for nutrient leakage loss on karst trough valley slopes. This study aimed to a) reveal the effects of the bedrock dip angle on the characteristics of nutrient leakage loss on dip-parallel/dip-perpendicular slopes and b) determine the bedrock dip angle threshold for nutrient leakage loss in karst trough valleys. To achieve this objective, the geographical structure of a karst trough valley slope was simulated using a newly designed steel experimental flume and a monoclinal bedrock tilt, respectively. The results revealed that i) for a flat bedrock dip angle of 10°, the surface runoff-associated TN and TP pollution moduli were maximal for dip-parallel slopes, while the underground sediment-associated nutrient leakage loss is minimum on dip-perpendicular slope. ii) Under dip-perpendicular slopes, 40° was the critical bedrock dip angle for underground runoff-associated nutrient leakage loss. iii) Surface TN and TP losses on dip-parallel slopes were always higher than those of dip-perpendicular slopes, and underground nutrient leakage showed the opposite trend. The underground sediment-associated nutrient loss rate was dominant under steep rock dip angle, and the opposite was found for flat and gentle rock dip angle conditions. These results could provide a theoretical foundation for controlling agricultural non-point source pollution and modelling in karst trough valleys under similar conditions.

基岩倾角是岩溶槽谷斜坡上养分泄漏损失的关键因素。这项研究的目的是：a）揭示基岩倾角对垂向平行/垂线垂直斜坡上养分泄漏损失特征的影响，以及b）确定岩溶槽谷中养分泄漏损失的基岩倾角阈值。为了实现这一目标，分别使用新设计的钢制实验水槽和单斜基岩倾斜度对喀斯特槽谷斜坡的地理结构进行了模拟。结果表明：i）在基岩倾角为10°的情况下，与倾斜平行的坡面，与地表径流相关的总氮和总磷污染模量最大，而与垂线垂直的坡面，地下沉积物相关的养分渗漏损失最小。 。ii）在垂直倾角下，40°是地下径流相关养分泄漏损失的临界基岩倾角。iii）倾斜平行坡面的总氮和总磷损失总是高于垂直倾斜面，地下养分渗漏呈现相反的趋势。在陡峭的岩石倾角下，地下沉积物相关的养分流失率占主导，而在平坦和缓和的岩石倾角条件下，则相反。这些结果可为在相似条件下控制喀斯特谷地农业面源污染和建模提供理论依据。与地下养分泄漏呈相反趋势。在陡峭的岩石倾角下，地下沉积物相关的养分流失率占主导，而在平坦和缓和的岩石倾角条件下，则相反。这些结果可为相似条件下控制喀斯特谷地农业面源污染和建模提供理论依据。与地下养分泄漏呈相反趋势。在陡峭的岩石倾角下，地下沉积物相关的养分流失率占主导，而在平坦和缓和的岩石倾角条件下，则相反。这些结果可为在相似条件下控制喀斯特谷地农业面源污染和建模提供理论依据。