The impact of freeze-thaw cycles and soil moisture content at freezing on runoff and soil loss

Authors: WEI, XIA - Lanzhou University; Huang, Chi Hua; WEI, NING - Northwest Agricultural & Forestry University; ZHAO, HENGCE - Lanzhou University; HE, YAN - Lanzhou University; WU, XIAODONG - Chinese Academy Of Sciences

Submitted to: Land Degradation and Development
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/5/2018
Publication Date: 1/1/2019
Citation: Wei, X., Huang, C., Wei, N., Zhao, H., He, Y., Wu, X. 2019. The impact of freeze-thaw cycles and soil moisture content at freezing on runoff and soil loss. Land Degradation and Development. 30:515-523. https://doi.org/10.1002/ldr.3243.
DOI: https://doi.org/10.1002/ldr.3243

Interpretive Summary: Freezing and thawing has been known to change aggregate stability and affect soil erosion. However, investigating soil erosion after freeze-thaw (F-T) cycles can be challenging because F-T cycle affects the soil moisture content, surface hydrology and flow hydraulics involved in processes of erosion. Experiments were conducted to assess the effects of F-T cycle and soil moisture content at time of freezing on soil erosion. The test soil were adjusted to 10% and 20% moisture content and subjected to 1, 3 and 6 F-T cycles. After each F-T cycle treatment, the soil was tested under a simulated rainstorm for its erosion response. The results showed that freeze-thaw cycles and soil moisture content increased runoff and erosion at different rainfall intensities. The impact of 20% soil moisture content was more pronounced than the 10% moisture on runoff and erosion for the same number of F-T cycles and rainfall intensities. The influence of F-T cycle on runoff and soil erosion increased as the number of F-T cycle was increased. Moreover, the impact of soil moisture content was greater than the impact from an increased number of F-T cycles. The important message from this research is that soil moisture content at the time of freezing and thawing is a key factor affecting the stability and erosional response of the soil. Results from these experiments are useful for estimating erosion model parameters when assessing soil erosion affected by freezing and thawing.

Technical Abstract: Investigating soil erosion processes after freeze-thaw (F-T) cycles can be challenging because F-T cycle affects the soil moisture content, surface hydrology and flow hydraulics involved in processes of erosion. Data collected from well-controlled experiments can help improve our understanding and modeling of the F-T impacted erosion processes. Experiments were conducted to assess the effects of F-T cycles and soil moisture content at time of freezing on soil erosion under simulated rainfall. The prepared soil were adjusted to 10% and 20% moisture content, placed in a sealed container and subjected to 1, 3 and 6 F-T cycles with freezing at -15 C for 24 h and followed by thawing at 4 C for 24 h. After each designed F-T cycle, the soil was air-dried and subjected to simulated rainfall to quantify the F-T effect on erosion. The results showed that freeze-thaw cycles and soil moisture content increased runoff and erosion rates at different rainfall intensities. The 20% soil moisture content showed more effect than 10% soil moisture on runoff and erosion for the same number of freeze-thaw cycles and rainfall intensities. The influence of freeze-thaw cycle on runoff and soil erosion was increased as the number of freeze-thaw cycles rising from 1, 3 to 6 under 10% soil moisture. However, the influence increased as the number of freeze-thaw cycle rising from 1 to 3 whereas decreased as the number of freeze-thaw cycle rising from 3 to 6 under 20% soil moisture content. Moreover, the impact of soil moisture content was greater than the number of freeze-thaw cycles on runoff and erosion under the same rainfall intensity. Results from these experiments will be useful for estimating erosion model parameters for predicting erosion affected by freezing and thawing.