Effects of preferential flow on soil nutrient transport in karst slopes after recultivation

Abstract In response to the global food shortage, a large amount of abandoned land in karst areas has been reclaimed as cultivated land, causing severe nonpoint source pollution. Preferential flow-driven soil nutrient transport on slopes remains poorly studied, though it is major factor pollution, responds changes caused by reclamation. We explored characteristics preferential flow differences recultivated grassland, and shrubland from returning farmland dye tracer experiments quantitatively examined effect transport. Under condition 40 mm precipitation, paths (PFPs) three types plots were mainly distributed 0 cm. The total porosity 20–40 cm layer was significantly reduced reclamation, number preferred 60 less than 10, which that grassland shrubland. But, reclamation results more nutrients flow. contribution rate other indexes contrast shrubland, lower zero, except for organic matter potassium. Moreover, when PFP connected rock–soil interface, water can leak underground through interface quickly. Therefore, our findings indicated reduces distribution depth PFP. Still, connection increases deep fissures even rivers, thereby become one main sources groundwater pollution areas.