Regulatory role of permanent gullies in dissolved nitrogen and phosphorus transport under different rainfall types.
Saved in:
| Title: | Regulatory role of permanent gullies in dissolved nitrogen and phosphorus transport under different rainfall types. |
|---|---|
| Authors: | Chen, Zhuoxin1,2 (AUTHOR), Guo, Mingming2 (AUTHOR) guomingming@iga.ac.cn, Wang, Lixin2,3,4 (AUTHOR), Liu, Xin2 (AUTHOR), Jian, Jinshi1 (AUTHOR), Chen, Qiang5 (AUTHOR), Zhang, Xingyi2 (AUTHOR) |
| Source: | Hydrology & Earth System Sciences. 2026, Vol. 30 Issue 10, p3351-3366. 16p. |
| Subject Terms: | *Nonpoint source pollution, *Rainfall, *Agricultural pollution, *Nutrient cycles, *Rainfall anomalies |
| Abstract: | Understanding how permanent gullies regulate the transport of dissolved ammonium (NH 4+), nitrate (NO 3-), and phosphorus (P) in runoff delivered from agricultural hillslopes under different rainfall types is essential for controlling non-point source pollution in agroecosystems. In this study, we selected two agricultural catchments, each containing a single permanent gully, and monitored runoff at the gully head and the gully outlet during the rainy seasons of 2022 and 2023. Runoff samples were filtered through 0.45 µ m membrane filters and analyzed for dissolved NH 4+ , NO 3- , and P concentrations, and the corresponding nutrient transport fluxes were then calculated. Based on event-scale rainfall characteristics, including rainfall depth, duration, average intensity, maximum 30 min intensity, and erosivity, rainfall events were classified using the k-means method to examine how different rainfall types influenced the role of gullies in the transport of dissolved NH 4+ , NO 3- , and P. The results showed that: (1) Gullies significantly enhanced runoff generation, contributing 36.1 % of total runoff despite occupying only 12.4 % of the catchment area. This contribution varied across rainfall types (Type A: frequent, low-depth, low-erosivity; Type B: short-duration, high-intensity; Type C: long-duration, high-erosivity) and was highest under Type A (43.2 %) and lowest under Type C (33.8 %). (2) Gullies exerted a pronounced dilution effect on dissolved NH 4+ , NO 3- , and P concentrations, particularly on dissolved NO 3- (dilution ratio: 0.65). Consequently, the contribution of gullies to dissolved NH 4+ , NO 3- , and P transport fluxes was lower than that to runoff volume, accounting for 31.4 %, 22.4 %, and 31.1 % of dissolved NH 4+ , NO 3- , and P transport fluxes at the outlet, respectively. (3) Type C rainfall dominated the transport of dissolved NH 4+ , NO 3- , and P. Only 10.2 % of events contributed over 68 % of dissolved NH 4+ , NO 3- , and P transport fluxes at the catchment scale and markedly increased their transport sensitivity to rainfall compared to Type A and Type B. These sensitivities were also intensified by gullies. These findings highlight the importance of prioritizing permanent gullies and high-erosivity rainfall events in strategies to reduce dissolved nutrient losses from agricultural catchments. [ABSTRACT FROM AUTHOR] |
| Database: | Energy & Power Source |
|
Full text is not displayed to guests.
Login for full access.
|
|
| Abstract: | Understanding how permanent gullies regulate the transport of dissolved ammonium (NH 4+), nitrate (NO 3-), and phosphorus (P) in runoff delivered from agricultural hillslopes under different rainfall types is essential for controlling non-point source pollution in agroecosystems. In this study, we selected two agricultural catchments, each containing a single permanent gully, and monitored runoff at the gully head and the gully outlet during the rainy seasons of 2022 and 2023. Runoff samples were filtered through 0.45 µ m membrane filters and analyzed for dissolved NH 4+ , NO 3- , and P concentrations, and the corresponding nutrient transport fluxes were then calculated. Based on event-scale rainfall characteristics, including rainfall depth, duration, average intensity, maximum 30 min intensity, and erosivity, rainfall events were classified using the k-means method to examine how different rainfall types influenced the role of gullies in the transport of dissolved NH 4+ , NO 3- , and P. The results showed that: (1) Gullies significantly enhanced runoff generation, contributing 36.1 % of total runoff despite occupying only 12.4 % of the catchment area. This contribution varied across rainfall types (Type A: frequent, low-depth, low-erosivity; Type B: short-duration, high-intensity; Type C: long-duration, high-erosivity) and was highest under Type A (43.2 %) and lowest under Type C (33.8 %). (2) Gullies exerted a pronounced dilution effect on dissolved NH 4+ , NO 3- , and P concentrations, particularly on dissolved NO 3- (dilution ratio: 0.65). Consequently, the contribution of gullies to dissolved NH 4+ , NO 3- , and P transport fluxes was lower than that to runoff volume, accounting for 31.4 %, 22.4 %, and 31.1 % of dissolved NH 4+ , NO 3- , and P transport fluxes at the outlet, respectively. (3) Type C rainfall dominated the transport of dissolved NH 4+ , NO 3- , and P. Only 10.2 % of events contributed over 68 % of dissolved NH 4+ , NO 3- , and P transport fluxes at the catchment scale and markedly increased their transport sensitivity to rainfall compared to Type A and Type B. These sensitivities were also intensified by gullies. These findings highlight the importance of prioritizing permanent gullies and high-erosivity rainfall events in strategies to reduce dissolved nutrient losses from agricultural catchments. [ABSTRACT FROM AUTHOR] |
|---|---|
| ISSN: | 10275606 |
| DOI: | 10.5194/hess-30-3351-2026 |
