Location: Agricultural Systems ResearchTitle: Freeze-thaw cycles effects on soil physical properties under different degraded conditions in Northeast China
|MA, QIANHONG - Beijing Normal University|
|ZHANG, KELI - Beijing Normal University|
|Jabro, Jalal "jay"|
|REN, LE - London School Of Economics|
|LIU, HONGYUAN - Northeast Institute Of Geography And Agronomy, Cas|
Submitted to: Environmental Earth Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2019
Publication Date: 5/15/2019
Citation: Ma, Q., Zhang, K., Jabro, J.D., Ren, L., Liu, H. 2019. Freeze-thaw cycles effects on soil physical properties under different degraded conditions in Northeast China. Environmental Earth Sciences. https://doi.org/10.1007/s12665-019-8323-z.
Interpretive Summary: Crop productivity in the black soil region in China has continued to be threatened by serious soil erosion as a result of more than 100 years of intense cultivation. In order to control regional soil loss it is thus necessary to understand the effects of freeze-thaw cycles on the erosion process A USDA-ARS scientist located in Sidney MT collaborated with Chinese researchers at Normal Beijing University to compare the responses of different degraded soils to freeze-thaw cycles. The study involved dividing the degraded soil surface into five types: original profile, degraded profile, parent profile, deposited profile and compacted surface. Simulated results revealed that the physical properties of soil were significantly affected by freeze-thaw cycles; however, the response was a function of the surface type on a slope. The soil porosity and water flow increased while the aggregate size decreased in samples from any surface condition following subjection of the soil to 30 freeze-thaw cycles; this was the result of changes in the soil structure caused by shrinking and swelling actions during freezing and thawing processes. In addition, soil aggregates were smaller in compacted soil than in other four types. The water-holding capacity significantly increased for the original and deposited profiles, however, it decreased strongly for the compacted surface, and no significant differences were observed for the degraded and parent profiles. The available water capacity was enhanced by the freeze-thaw cycles for each type and the water holding-capacity was smaller in the degraded and parent profiles than in the other conditions. In general, well-structured soils exhibited stronger resistance to the disruptive effects of repeated freeze-thaw cycles. The results of this study could help to explain the effect of the mechanism of freeze-thaw cycles on the physical properties of soils and improve the prediction of soil loss and runoff on slope scales. The results also demonstrate that freeze-thaw process could contribute to soil erosion prediction in U.S. cold climates.
Technical Abstract: The influence of freeze-thaw cycles (FTCs) on soil physical properties and the erosion processes has been reported extensively. Nevertheless, the previous results were restricted in simulating runoff and soil loss on cropping slopes in the cold region; this was the result of soil not responding under different degraded conditions to FTCs. Our study was designed to compare and quantify the responses of different degraded soils to FTCs in a laboratory setting. This study involved dividing the degraded soil surface into five types: original profile, degraded profile, parent profile, deposited profile and compacted surface. The samples of the five soil types were collected from the black soil region in Northeast China and were frozen and thawed repeatedly 30 times at -12' for 12 h and at 8' for 12 h, respectively. The samples not subjected to FTCs were designated the control group. Following repetition of the FTCs, the porosity ( ), the mean weight diameter (MWD) of aggregates, the saturated hydraulic conductivity (Ks) and the water retention curves of the tested soil were measured. Results showed that and Ks significantly increased after subjection to repeated FTCs; the increase of was highest for the degraded profile. The MWD of aggregates decreased significantly due to FTCs; the degradation of the compacted surface was the highest. Compared with the unfrozen control group, the remaining water contents under a predetermined pressure potential significantly increased in the deposited and original profiles and significantly decreased in the compacted surface; no significant differences were found in the degraded and parent profiles. The available water capacity (AWC) increased for each condition after 30 FTCs and there was less retained water in the degraded and parent profiles than in other profiles. These findings may help improve the understanding of the functional mechanism of FTCs on the soil erosion process.