TY - JOUR

T1 - Tillage induces rapid loss of organic carbon in large macroaggregates of calcareous soils

AU - Ye, Yingying

AU - Xiao, Shuangshuang

AU - Liu, Shujuan

AU - Zhang, Wei

AU - Zhao, Jie

AU - Chen, Hongsong

AU - Guggenberger, Georg

AU - Wang, Kelin

N1 - Funding Information: This work was supported by the National Key Research and Development Program of China (grant number 2016YFC0502406 ), the Strategic Priority Research Program of the Chinese Academy of Sciences (grant number XDA23060103), the International Partnership Program of Chinese Academy of Sciences (132852KYSB20170029), the National Natural Science Foundation of China [grant numbers 41930652 and 31870502 ], the "West Light" Project of the Chinese Academy of Sciences to Ye Yingying, the Open Fund of Key Laboratory of Agro-ecological Processes in Subtropical Region, Chinese Academy of Sciences (grant number ISA2019303), and the Guangxi Bagui Scholarship Program to Dejun Li . We would also like to extend our sincere gratitude to the editor and reviewers for their comments. Appendix A

PY - 2020/5

Y1 - 2020/5

N2 - Soil organic carbon (SOC) sequestration and protection not only mitigate CO2 emission but also promote soil fertility. Naturally, calcareous soils in the karst area contain significantly higher SOC concentration than the red soils in non-karst area of the same region. After cultivation, calcareous soils are susceptible to SOC loss, with substantial SOC loss occurring within two years. However, the underlying mechanisms are not well understood. To expand our understanding of the process of rapid SOC loss and the role played by soil aggregate disruption, we conducted a 1-year in situ study in a karst area in Southwest China. We tilled the soil at different intervals—every 6 (T1), 4 (T2), 2 (T3), and 1 (T4) months—causing aggregate disruption of different intensities. No-tillage soil (T0) was treated as a control. After 1 year, the SOC concentration in the soil under the tillage treatments (T1, T2, T3, and T4) was significantly reduced; however, in the no-tillage soil, no significant change was observed. The SOC loss within the first 3 months accounted for approximately 70 %–84 % of the total SOC loss, indicating that SOC loss was most pronounced during the initial tillage period. SOC was mainly stored in the 2–8 mm soil aggregates. Tillage-induced disruption of the 5–8 mm aggregates resulted in a decline of the physical protection of SOC, leading to substantial SOC loss from these aggregates. Besides, the SOC loss was positively correlated to the amount of Ca2+ leaching, indicating that enhanced carbonate dissolution might contribute to the decline in aggregate stability and associated SOC loss. Our results emphasize the importance of zero-tillage management and maintenance of large soil macroaggregates for sustainable land use of calcareous soils in karst regions.

AB - Soil organic carbon (SOC) sequestration and protection not only mitigate CO2 emission but also promote soil fertility. Naturally, calcareous soils in the karst area contain significantly higher SOC concentration than the red soils in non-karst area of the same region. After cultivation, calcareous soils are susceptible to SOC loss, with substantial SOC loss occurring within two years. However, the underlying mechanisms are not well understood. To expand our understanding of the process of rapid SOC loss and the role played by soil aggregate disruption, we conducted a 1-year in situ study in a karst area in Southwest China. We tilled the soil at different intervals—every 6 (T1), 4 (T2), 2 (T3), and 1 (T4) months—causing aggregate disruption of different intensities. No-tillage soil (T0) was treated as a control. After 1 year, the SOC concentration in the soil under the tillage treatments (T1, T2, T3, and T4) was significantly reduced; however, in the no-tillage soil, no significant change was observed. The SOC loss within the first 3 months accounted for approximately 70 %–84 % of the total SOC loss, indicating that SOC loss was most pronounced during the initial tillage period. SOC was mainly stored in the 2–8 mm soil aggregates. Tillage-induced disruption of the 5–8 mm aggregates resulted in a decline of the physical protection of SOC, leading to substantial SOC loss from these aggregates. Besides, the SOC loss was positively correlated to the amount of Ca2+ leaching, indicating that enhanced carbonate dissolution might contribute to the decline in aggregate stability and associated SOC loss. Our results emphasize the importance of zero-tillage management and maintenance of large soil macroaggregates for sustainable land use of calcareous soils in karst regions.

KW - Calcareous soil

KW - Karst ecosystem

KW - Soil aggregate

KW - Soil organic carbon

KW - Tillage

UR - http://www.scopus.com/inward/record.url?scp=85077801302&partnerID=8YFLogxK

U2 - 10.1016/j.still.2019.104549

DO - 10.1016/j.still.2019.104549

M3 - Article

AN - SCOPUS:85077801302

VL - 199

JO - Soil and Tillage Research

JF - Soil and Tillage Research

SN - 0167-1987

M1 - 104549

ER -