Effects of Surface-Underground Runoff Regulated by Biochar on Nutrient Loss in Karst Mountainous Areas

• Published in: Journal of soil science and plant nutrition Vol. 23; no. 3; pp. 3163 - 3173
• Main Authors: Fan, Chunhua, Yin, Xiaoai, Fang, Qian, Yang, Xiuchao, Zhao, Longshan
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.09.2023; Springer Nature B.V
• Subjects: Agricultural production; Agriculture; Biomass; Biomedical and Life Sciences; Carbon; Charcoal; Ecology; Environment; Eutrophication; Flow paths; Food security; Hydrology; Infiltration capacity; Karst; Life Sciences; Mountain regions; Mountainous areas; Mountains; Nitrogen; Nutrient flow; Nutrient loss; Nutrients; Original Paper; Phosphorus; Plant Sciences; Potassium; Rain; Rainfall; Rainfall intensity; Raw materials; Runoff; Soil erosion; Soil infiltration; Soil Science & Conservation; Soil structure; Soil water; Surface runoff; China; Nutrient output; Biochar; Karst mountainous areas; Surface runoff; Underground fissure runoff
• ISSN: 0718-9508; 0718-9516
• DOI: 10.1007/s42729-023-01374-5

In this study, the effect of biochar application on soil erosion and nutrient loss on karst slopes was investigated under dual surface-underground flow path conditions. Four application rates of biochar to soil considered (0 t ha −1 (CK), 15 t ha −1 (B15), 30 t ha −1 (B30), and 60 t ha −1 (B60)). The experiment was conducted by simulating rainfall, the rainfall intensity was set to 50 mm h −1 , and the slope was 25°. Measurement indications are the following: surface runoff (SR), subsurface runoff (SBR), underground fissure runoff (UFR), and concentrations and output loads of total carbon (TC), total nitrogen (TN), total phosphorus (TP), and total potassium (TK) in runoff. The results showed that compared to those under CK, biochar increased SR by 98.92–172.40% and decreased SBR and UFR by 72.69–77.00% and 43.07–94.71%, respectively. Biochar reduced the TC concentration in UFR with increasing biochar application rate, while there were no obvious patterns of the TC concentration in SR and SBR. Compared to those under CK, the TN concentration in SR decreased under the B15, B30, and B60 treatments, while it increased in SBR with almost no difference in UFR. There was no significant difference ( P  > 0.05) in the TP concentration among the four treatments. The output of TC, TP, and TK through SR dominated accounting for 60–97% of the total load. However, the TN output load in SR was low, and the proportion of its load in the total output load was less than 30%. This study concluded that compared to those in the absence of biochar application, the biochar treatment increased SR by 98.92–172.40%, but reduced the SBR and UFR by 43.07–94.71%. Biochar application increased the total output loads of TC, TP, and TK but decreased the total output load of TN. In summary, biochar alters the pore structure of karst soil, reduces the soil infiltration capacity, and ultimately increases SR and decreases UFR. More importantly, biochar application plays a vital role in regulating water, soil, and nutrient loss at the surface and underground flow paths in karst slopes. Moreover, biochar reduces the TN loss. The results can provide a theoretical basis for the study of the influence mechanism of biochar on soil erosion and the nutrient output in karst mountainous areas.