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Chinese Journal of Applied Ecology ›› 2022, Vol. 33 ›› Issue (6): 1475-1481.doi: 10.13287/j.1001-9332.202206.013

• Special Features of Stable Isotope Ecology • Previous Articles     Next Articles

Distribution and sequestration of straw carbon in surface and deep soil aggregates under different fertilization treatments

DUAN Jia-ru1, WANG Shu-ying1, LI Xiao-hong1, XU Xiang-ru2, MEI Xiu-wen1, AN Ting-ting1*, WANG Jing-kuan1   

  1. 1College of Land and Environment, Shenyang Agricultural University/Key Laboratory of Northeast Arable Land Conservation, Ministry of Agriculture and Rural Affair/National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, Shenyang 110866, China;
    2College of Agricultural Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, China
  • Received:2021-09-06 Accepted:2022-04-05 Online:2022-06-15 Published:2022-12-15

Abstract: Long-term fertilization causes the differences in water, heat, nutrients and microbial activities between topsoil and deep soil, with consequences on the decomposition and turnover of straw carbon (C) in soils. At a long-term positioning experimental station in Shenyang Agricultural University, we mixed the topsoil (0-20 cm) and deep soil (40-60 cm) samples from different fertilization treatments with 13C-labeled straw for in-situ incubation. We analyzed the content of organic C and its δ13C value in soil aggregates, compared the difference in the distribution of straw C between topsoil and deep soil aggregates, and explored the effects of fertilization on the sequestration of straw C in soil aggregates. Compared with fertilization treatments (i.e., single chemical nitrogen fertilizer application and combination of organic manure with nitrogen fertilizer application), the treatment without fertilization increased the content of straw C of <0.053 mm aggregate in the topsoil by 106.7% and that of >0.25 mm aggregate in the deep soil by 34.2%. The contribution percentage of straw C to organic C of >0.053 mm aggregate in the deep soil was about two times of that in the topsoil. About 22.6% and 11.4% of straw C was distributed into the >0.25 mm and <0.25 mm aggregates of topsoil, and about 29.4% and 8.8% of straw C was distributed into the >0.25 mm and <0.25 mm aggregates of deep soil, respectively. In conclusion, straw addition promoted the regeneration and sequestration of carbon in deep soil macroaggregates and increased the carbon sequestration potential of deep soil.

Key words: aggregate, straw carbon, deep soil, 13C-labeling, fertilization