Residue cover and rainfall intensity effects on runoff soil organic carbon losses

• Published in: Catena (Giessen) Vol. 78; no. 1; pp. 81 - 86
• Main Authors: Jin, K., Cornelis, W.M., Gabriels, D., Baert, M., Wu, H.J., Schiettecatte, W., Cai, D.X., De Neve, S., Jin, J.Y., Hartmann, R., Hofman, G.
• Format: Journal Article
• Language: English
• Published: Cremlingen-Destedt Elsevier B.V 15-07-2009; Catena
• Subjects: Bgi / Prodig; Cover percentage; Particle size distribution; Pedology; Physical geography; Rainfall intensity; Rainfall simulation; Runoff sediment; Soil organic carbon loss; China; Rainfall simulation; Soil organic carbon loss; Particle size distribution; Runoff sediment; Rainfall intensity; Cover percentage; Loess; Agricultural practice; Plateau; Soil erosion; Organic materials; Sediment budget; Grain size distribution; Precipitation; Agropedology; Runoff; Nutrient; Erosion control
• ISSN: 0341-8162; 1872-6887
• DOI: 10.1016/j.catena.2009.03.001

Soil cover and rainfall intensity (
RI) are recognized to have severe impacts on soil erosion and an interaction exists between them. This study investigates the effect of rainfall intensity (
RI) and soil surface cover on losses of sediment and the selective enrichment of soil organic carbon (SOC) in the sediment by surface runoff. A field rainfall simulator was used in the laboratory to produce 90 min rainfall events of three rainfall intensities (65, 85 and 105 mm h
−
1
) and four cover percentages (0%, 25%, 50% and 75%) on soil material at 9% slope. A strong negative exponential relation was observed between cover percentage and
RI on sediment loss under 85 and 105 mm h
−
1
of rain, while under
RI of 65 mm h
−
1
, the highest sediment loss was observed under 25% cover. Overall, higher
RI and lower cover produced higher sediment and consequently higher nutrient loss, but resulted in a lower SOC enrichment ratio (ER
SOC) in the sediment. The amount of runoff sediment rather than the ER
SOC in the sediment was the determinant factor for the amount of nutrients lost. The values of ER
SOC were high and positively correlated with the ER values of particles smaller than 20 µm (
p
<
0.01). Although the sediment contained substantially more fine fractions (fine silt and clay, <
20 µm), the original soil and runoff sediment were still of the same texture class, i.e. silt clay loam.