Comparison of runoff and soil loss in different tillage systems in the Mollisol region of Northeast China

Authors: XU, XIMENG - Northwest Agriculture And Forestry University; ZHENG, FENLI - Northwest Agriculture And Forestry University; Wilson, Glenn; HE, CHAO - Northwest Agriculture And Forestry University; LU, JIA - Northwest Agriculture And Forestry University; BIAN, FENG - Northwest Agriculture And Forestry University

Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/31/2017
Publication Date: 4/1/2018
Citation: Xu, X., Zheng, F., Wilson, G.V., He, C., Lu, J., Bian, F. 2018. Comparison of runoff and soil loss in different tillage systems in the Mollisol region of Northeast China. Soil & Tillage Research. 177 pp. 1-11. https://doi.org/10.1016/j.still.2017.10.005.
DOI: https://doi.org/10.1016/j.still.2017.10.005

Interpretive Summary: Longitudinal ridge tillage involves furrows running up and down the slope. It is the conventional tillage method in the cold region of Northeast China. Soil erosion is a serious problem in this region in part due to the use of this tillage system in a region with long slope lengths. Contour ridge systems are rare in this region and flat tillage is not practiced. It is unclear what the best tillage system and ridge orientation is for sustainable agriculture of this region. Thus, a series of simulated rainfall experiments were conducted to compare the runoff and soil loss in longitudinal (LRS) and contour ridge (CRS) systems to a flat tillage system (FTS). A large soil pan (8 m-long, 1.5 m-wide, and 0.6 m-deep) with a rainfall simulation system was used in this study with the three tillage systems (LRS, CRS, FTS) under three rainfall intensities (50, 75 and 100 mm h-1) at a critical slope gradient of 5°. The results showed that runoff and soil loss in the LRS were larger than those in the CRS and FTSs due to a shift in erosion from sheet to concentrated flow erosion along furrows. Failure of contour ridges occurred in the 75 and 100 mm h-1 treatments when water stored in furrows exceeded their storage capacity and overflow of the ridges occurred. Failure of ridges changed the runoff and soil loss by providing a large sediment source to the convergent flow channels that cut through the ridges. Water storage of CRS furrows was constant as rainfall intensity varied which led to overtopping during large storm conditions. Modifications of the conventional LRS by shifting to CRS to retain more rainwater and snowmelt water during low to moderate rainfall events is recommended as this would reduce soil loss and enhance infiltration. However, the FTS exhibited the lowest runoff and erosion across all conditions and is recommended for for large storm event conditions.

Technical Abstract: Longitudinal ridge tillage is the conventional tillage method in the cold, Mollisol region of Northeast China in which furrows are oriented up and down the slope. Soil erosion is a serious problem in this region in part due to the use of this tillage system with long slope lengths. It is unclear what the best tillage system and ridge orientation is for sustainable agriculture of this region. Thus, a series of simulated rainfall experiments were conducted to compare the runoff and soil loss in longitudinal (LRS) and contour ridge (CRS) systems to a flat tillage system (FTS). A large soil pan (8 m-long, 1.5 m-wide, and 0.6 m-deep) and a side sprinkler rainfall simulation system were used in this study with the three tillage systems (LRS, CRS, FTS) under three rainfall intensities (50, 75 and 100 mm h-1) at a critical slope gradient of 5°. The results showed that runoff and soil loss in the LRS were larger than those in the CRS and FTSs due to a shift in erosion from sheet to concentrated flow erosion along furrows which led to shear stress increase. Failure of contour ridges occurred in the 75 and 100 mm h-1 treatments by breaching of ridges when water stored in furrows exceeded their capacity. Breaching changed the runoff and soil loss by providing a large sediment source to the convergent flow channels. Water storage of CRS furrows was constant as rainfall intensity varied which led to overtopping during large storm conditions. Modifications of the conventional LRS by shifting to CRS to retain more rainwater and snowmelt water during low to moderate rainfall events is highly recommended as this would reduce soil loss and enhance infiltration in the Mollisol region of Northeast China. The FTS exhibited the lowest runoff and erosion across all conditions and is recommended for the Mollisol region for large storm event conditions.