Song L. Y. auteur aut IRD Ribolzi Olivier auteur aut IRD Boithias L. auteur aut IRD Xayyathip Khampaseuth auteur aut IRD Valentin Christian auteur aut IRD Soulileuth B. auteur aut IRD Robain Henri auteur aut IRD De Rouw Anneke auteur aut IRD Sounyafong P. auteur aut IRD Silvera Norbert auteur aut IRD Sisouvanh P. auteur aut IRD Janeau Jean-Louis auteur aut IRD Saveng I. auteur aut IRD Oeurng C. auteur aut IRD Pierret Alain auteur aut IRD text journalArticle eng text/pdf reformatted digital access Riparian grass buffers reduce the velocity of water flowing over the soil surface during storms, capturing surface runoff (SR) and trapping soil particles eroded from cultivated slopes. Rarely quantified under steep slope conditions (>45 %), this phenomenon probably occurs in many mountain agroecosystems in the humid tropics. In Southeast Asia, teak plantations are often established on steep slopes where they can lead to significant soil loss (SL), particularly when the understory is removed. Therefore, we aimed to: quantify the effect of riparian grass buffers on SR and SL downstream of a teak plantation; and estimate the trapping efficiency of riparian grass buffers for water (WTE) and sediment (STE). Field measurements were carried out in Northern Lao PDR during the2014 rainy season, considering riparian zones with contrasted ground covers: (1) uncovered (URZ - 7-year-old teak trees with mean grass and litter densities of 7 % (SD 2 %) and 4 % (SD 3 %), respectively; (2) transitional (TRZ - 7-year-old teak trees with mean grass and litter densities of 19 % (SD 10 %) and 56 % (SD 9 %), respectively; and (3) covered (CRZ - grassed areas without teak trees with mean grass and litter densities of 46 % (SD 13 %) and 47 % (SD 21 %), respectively). WTE and STE were estimated based on measurements carried out from 6 July to 6 September2014 under natural rainfall conditions, using pairs of triplicate Gerlach troughs installed at the upper and lower margins of 5- and 10-m riparian sections (encompassing areas of similar to 25 and 50 m(2), respectively). Runoff coefficient (Rc), SL, and soil surface features were measured on the occasion of 20 rainfall events in 1-m(2) microplots. Rc and SL were higher in URZ (56 %, 5791 g<middle dot>m(-2)) than in TRZ (13 %, 250 g<middle dot>m(-2)) and CRZ (19 %, 159 g<middle dot>m(-2)). Median WTE and STE were the highest along the 10-m TRZ + CRZ riparian grass buffer at 85 % and 97 % respectively. Partial Least Square Regression (PLSR) modelling yielded a good agreement between observation and prediction for WTE and STE at seasonal scale. Overall, the results of this work indicate that 5 to 10 m riparian grass buffers limit the export of surface water and sediment downstream during small (24-h rainfall <= 20.9 mm<middle dot>d(-1), return period <= 1 year) to large storms (40.0 mm<middle dot>d(-1) < 24-h rainfall <= 84.5 mm<middle dot>d(-1), 1.01 year<return period <= 2 years). specialized Southeast Asia Tropical agroecosystems Soil loss mitigation Nature-based solutions Ecosystem services LAOS ASIE DU SUD EST ZONE TROPICALE 021 068 076 062 212 107537 [14 p.] 2025 0925-8574 https://www.documentation.ird.fr/hor/fdi:010092780 10.1016/j.ecoleng.2025.107537 0925-8574 [F B010092780] https://www.documentation.ird.fr/hor/fdi:010092780 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2025-04/010092780.pdf IRD - Base Horizon / Pleins textes 2025-04-02 2025-06-13 fdi:010092780 fre