Acta Geographica Sinica ›› 2020, Vol. 75 ›› Issue (3): 558-570.doi: 10.11821/dlxb202003009

• Surface Process • Previous Articles     Next Articles

Spatial characteristics and variation mechanism of different soil organic carbon components in the alluvial/sedimentary zone of the Yellow River

ZHANG Junhua1,2, LI Guodong1,2(), WANG Yansong1,2, ZHU Lianqi1,2, ZHAO Wenliang1,2, DING Yapeng1,2   

  1. 1. Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions (Henan University), Ministry of Education, Kaifeng 475004, Henan, China
    2. College of Environment and Planning, Henan University, Kaifeng 475004, Henan, China
  • Received:2019-05-17 Revised:2020-01-14 Online:2020-03-25 Published:2020-05-25
  • Contact: LI Guodong E-mail:defsky@163.com
  • Supported by:
    National Natural Science Foundation of China(41101088);Natural Science Foundation of Henan Province(182300410129);New Interdisciplinary and Characteristic Subject Cultivation Project of Henan University

Abstract:

Sediment from the Yellow River is the main material source in the formation of several landform types in the lower reaches of the Yellow River. This sediment deposition changes the surface soil structure and its organic carbon content. Here, the distribution characteristics of soil organic carbon components and their influencing factors were analyzed in the Kaifeng and Zhoukou areas based on field investigations, laboratory experiments and spatial analyses. The statistical results showed that the TOC, AOC and NOC contents were 0.05-30.03 g/kg, 0.01-8.86 g/kg and 0.02-23.36 g/kg, respectively. Contents were higher in the surface (0-20 cm) layer than those in the lower (20-100 cm) layer, and the sequence of change from high to low content in a single layer was TOC, AOC and NOC. The NOC content contributed to TOC more than AOC did. The geostatistical characteristics obtained by using the GS+ software showed that the nugget coefficients of TOC, AOC and NOC were between 0.50 and 0.67, with a moderate degree of spatial correlation. This indicates that structural and random factors commonly influence variations in TOC, AOC and NOC, and that the action intensity between them is similar. The overall trend in all areas was that the contents of TOC, AOC and NOC were relatively consistent with those from the 0-20 cm to the 20-100 cm layer, although a transition from high-value region to low-value region was obvious. The spatial distribution and the statistical characteristics of TOC, AOC and NOC contents indicates that the high-value region is located in the area less affected by sediment, and the low-value region is located in the area which the Yellow River floods. The old riverway of the Yellow River has a value somewhere in between. In flooded areas, the TOC, AOC and NOC contents were the lowest in the burst place, and then contents gradually increased in the direction of water flow and passed area. Spatial variation in the NOC and AOC contents reflected the regions of TOC spatial variation and accumulation well. Throughout history, the banks of the Yellow River have been overflowed, causing river realignment and serious flooding. The resulting sediment deposition changed the surface particulate matter composition and soil organic matter content. It was found that the distribution of deposited sediment in the flooded area and old riverway of the Yellow River, the farming process and the cultivation history were all important factors affecting SOC composition content and spatial distribution. In addition, the organic matter input, soil particle composition and their dynamic relationship were the key factors affecting soil structure and organic carbon components. In short, increasing organic matter content and improving soil structure are effective ways to improve soil quality and to achieve sustainable regional agricultural development.

Key words: soil organic carbon, Yellow River sediment, spatial characteristics, farming history