Rainstorm pattern effects on the size distribution of soil aggregate in eroded sediment within contour ridge systems

• Published in: Journal of soils and sediments Vol. 20; no. 4; pp. 2192 - 2206
• Main Authors: An, Juan, Zhang, Yunqi, Wang, Yueyue
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2020; Springer Nature B.V
• Subjects: Aggregates; Computer simulation; Contours; Earth and Environmental Science; Environment; Environmental Physics; Falling; Information systems; Kinetic energy; Rain; Rainfall; Rainfall intensity; Rainstorms; Runoff; Sec 5 • Soil and Landscape Ecology • Research Article; Sediment; Shape; Size distribution; Soil aggregates; Soil erosion; Soil Science & Conservation; Soils; Stability; Storms; Tillage; Storm pattern; Rainfall simulation; The contour ridge system; Rainfall intensity occurring periods; Soil aggregate loss
• ISSN: 1439-0108; 1614-7480
• DOI: 10.1007/s11368-019-02561-7

Purpose Intra-storm temporal distributions of rainfall intensity (storm patterns) greatly affect soil erosion process within flat tillage systems, but limited information is available about its influence on the distribution characteristics of soil aggregate, especially within contour ridge system. Materials and methods In this study, a laboratory study of 12 rainfall simulation experiments was conducted to analyze the loss characteristic of 16 sizes aggregate in eroded sediment within contour ridge system under the rising, falling, rising–falling, and falling–rising patterns. All patterns included three rainfall intensities, 30, 60, and 90 mm h −1 , and comprised the same rainfall amount and kinetic energy. Results and discussion The results showed that storm patterns showed significant influence on soil aggregate loss. The rising–falling, falling–rising, and falling pattern had 1.43, 1.11, and 1.04 times soil aggregate loss greater than the rising pattern, respectively. Differences in size distribution of soil aggregate among storm patterns mainly concentrated on the most eroded size of microaggregate, especially 50–100 μm fraction. An intensity of 30 mm h −1 made the greatest contribution of 100.87%–511.93% to the diversity of soil aggregate loss following the storm pattern simulations relative to 60 and 90 mm h −1 intensities, likely resulting from erosion process, soil aggregate detachment, and runoff transport abilities from 30 mm h −1 intensity varying within storm pattern duration. The occurring periods of rainfall intensity significantly affected the loss of each size aggregate and showed the most obvious influence on 50–100 μm aggregate. Effects of storm pattern and rainfall intensity occurring periods were more pronounced with the increase of aggregate size at the macro-aggregate scale. Contour failure was easily to occur under the most prevalent storm pattern—falling and rising–falling patterns—which comprised 59.44% of soil aggregate loss. Conclusions Results recommended that more attention should be given to contour ridge stability, especially under falling and rising–falling patterns. Incorporating contour failure and the occurring context of rainfall intensity into the erosion model could successfully simulate soil aggregate loss characteristics, especially small-sized aggregates.