.png){kind=icon}
.png){kind=icon}
Return
Decoupled carbon and nitrogen responses to substrate addition as a legacy of dry–wet cycles in semi-arid cropland soil
.png){kind=icon}
PRE
AI
C
Y
X
D
DOI：10.1007/s11368-026-04484-6.png)
.png){kind=icon}
Original request for help.png){kind=icon}
Share.png){kind=icon}
Save
Abstract
En 中文
Climate models project more frequent and severe soil dry–wet (DW) events in semi-arid regions, but whether historical moisture stress leaves lasting effects on soil carbon (C) and nitrogen (N) transformations upon new organic inputs remains unclear. We investigated the legacy effects of four successive DW cycles on microbial C and N dynamics in a semi-arid cropland soil. After the pre-treatment, both continuously moistened (CM) and DW-exposed soils were rewet to the same moisture level with addition of concentrated oat straw leachate as a complex organic substrate. Soil respiration rates, microbial and soil C and N pools, metabolic quotient (qCO2), enzyme activities, and phospholipid fatty acid profiles were determined on days 0, 3, and 14. A history of DW cycles increased cumulative CO2-C release by 29% over the entire 14-day incubation period, with the legacy effect being more pronounced during the first 3 days (43.98% increase) than during the subsequent 3–14 days (16.25% increase). DW legacy elevated qCO2, reduced dissolved organic C, microbial biomass C, and the ratio of cumulative mineralized C to net mineralized N, but did not affect total inorganic N, microbial biomass N, and net N mineralization. These responses were accompanied by decreased abundances of Gram-negative bacteria and saprophytic fungi, and increased microbial stress indicators. Our results suggest a decoupling pattern in which historical DW cycles create a persistent microbial legacy that enhances C mineralization upon new substrate addition while leaving N transformations largely unaffected. Such positive C legacy effects, if persistent under field conditions, could reduce the capacity of these semi-arid cropland soils to sequester new organic C inputs under future precipitation regimes with intensified DW cycles; however, this possibility warrants longer-term field validation.
Keywords:
Drying‒rewetting cycles
Leachate organic carbon
Metabolic quotient
Microbial community composition
Soil carbon and nitrogen pools
Soil moisture history
Journal
IF:
3
Papers:
548
Citations:
1.1W
Organization
Cited Papers