JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2023, Vol. 47 ›› Issue (6): 51-60.doi: 10.12302/j.issn.1000-2006.202207042

Special Issue: 山水林田湖草一体化保护和生态修复——土壤侵蚀修复研究

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Spatio-temporal characteristic of soil loss on cropland slopes in different cultivation periods of the Black Soil Region in northeast China

YU Yue1(), ZHAO Lijun1, ZHANG Wei1, ZHANG Keli2,3, LIU Liang4   

  1. 1. School of Geography Science, Liaoning Normal University, Dalian 116029, China
    2. State Key Laboratory of Surface Process and Resources Ecology of the Department of Geography, Beijing Normal University, Beijing 100875, China
    3. School of Geography, Department of Geography, Beijing Normal University, Beijing 100875, China
    4. College of Forestry and Grassland, College of Soil and Water Conservation, Nanjing Forestry University, Nanjing 210037, China
  • Received:2022-07-29 Revised:2022-10-04 Online:2023-11-30 Published:2023-11-23

Abstract:

【Objective】The Black Soil Region is an important food base, which has a vital strategic position to ensure the food security in China. However, due to the long-term unreasonable utilization, the black soil resources suffered from serious water erosion. The objective is to clarify the spatio-temporal characteristic of soil loss on cropland and discuss the feasibility of evaluating soil erosion by magnetic susceptibility. 【Method】Magnetic susceptibility (MS) had been proved to be a rapid, reliable, economic and nondestructive method in estimating hillslope soil redistribution. In this paper, three typical black soil slope transects were selected in Heshan Farm, Heilongjiang Province, and collected soil profile samples from surface to 60-100 cm depth, measured soil magnetic susceptibility. The MS was used as a tracer to analyze the spatio-temporal heterogeneity of soil susceptibility at slope scale and discussed the soil erosion patterns in Black Soil Region. 【Result】The results showed that MS of topsoils on all the slope were generally high, and decreased with the increasing of soil depth. MS at parent layers become stable, which was in line with the MS characteristics of temperate soil developed from weak magnetic parent materials. The average MS at upperslopes and middleslopes were less than that of reference sites, which were 24.1×10-8 m3/kg and 24.8×10-8 m3/kg, respectively, the average MS of lowerslopes were greater than that of reference sites, for 39.71×10-8 m3/kg. It conformed to the general soil erosion pattern on hillslope that soil material deposited from its original position to the lower position. The whole slope were divided into erosion area and deposition area according to the topsoil MS of reference sites. The topsoil MS at the erosion area was lower than that of reference sites, while the topsoil MS at the deposition area was higher than that of reference sites. The topsoil particles were removed and transported at upperslopes and middleslopes, deposited at lowerslopes. With the increasing of cultivation periods, the MS between upperslopes and lowerslopes varied significantly which showed strong slope heterogeneity, and the cultivation periods were positively correlated to the soil redistribution. The range of MS on cropland reclaimed for 110 years was 1.7×10-8-88.7×10-8 m3/kg, which was about 1.4 and 1.9 times of cultivated for 60 and 30 a, respectively. 【Conclusion】The MS at topsoils of the black soil slope presented heterogeneity, that is, upperslopes and middleslopes located in the erosion area while lowerslopes were located in the deposition area. The longer the cultivation period, the higher the degree of soil redistribution on slope. Soil erosion was the most intense on the slope reclaimed 110 years ago. In view of the soil erosion in Black Soil Region, we should vigorously carry out the quality protection and improvement of cultivated land, encourage contour farming and strengthen the monitoring and investigation of soil conservation of black soil under a longer spatio-temporal series. The results can provide a theoretical basis for the prediction and prevention of water conservation and controlling soil erosion in Northeast China, which is conducive to the sustainable development of regional agriculture and ecological environmental protection.

Key words: water erosion, magnetic susceptibility, soil magnetic, cultivation periods, the Black Soil Region

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