Deep-rooted perennial crops differ in capacity to stabilize C inputs in deep soil layers
Leanne Peixoto1, Jørgen E Olesen2,3, Lars Elsgaard2,3
1Department of Agroecology, Aarhus University, Blichers Allé 20, 8830, Tjele, Denmark. leanne.peixoto@agro.au.dk.
Scientific Reports
|April 9, 2022
Summary
Deep-rooted perennial crops like lucerne and wheatgrass enhance soil carbon storage. Legumes, such as lucerne, show greater potential for microbial carbon stabilization in deeper soil layers.
Area of Science:
- Agricultural Science
- Soil Science
- Climate Change Mitigation
Background:
- Soil carbon storage is crucial for climate change mitigation.
- Deep-rooted perennial crops can enhance agricultural soils' capacity to act as carbon sinks.
- Understanding carbon allocation and stabilization in deep soil layers is essential.
Purpose of the Study:
- To compare carbon allocation and stabilization in deep soil layers (150 cm) between lucerne (Medicago sativa L.) and intermediate wheatgrass (Kernza; Thinopyrum intermedium).
- To investigate the influence of nitrogen (N) fertilizer rates on carbon input and stabilization in Kernza.
- To assess the role of legumes versus non-legumes in promoting microbial carbon stabilization.
Main Methods:
- Comparison of carbon (C) allocation and stabilization in deep soil profiles under lucerne and Kernza.
- Application of different mineral nitrogen (N) fertilizer rates (100 and 200 kg N ha⁻¹) to Kernza.
- Analysis of microbial biomass and N cycling genes in rhizosphere soil.
Main Results:
- Both lucerne and Kernza effectively transported carbon to deeper soil layers.
- Carbon input and stabilization in Kernza were decoupled from nitrogen fertilizer rates.
- Lucerne, a nitrogen-fixing legume, demonstrated a greater capacity for microbial carbon stabilization compared to Kernza.
- Lucerne increased microbial biomass and N cycling gene abundance in the rhizosphere, linked to amino acid rhizodeposition.
Conclusions:
- Deep-rooted perennial crops are effective in sequestering carbon in deeper soil horizons.
- Legumes, like lucerne, play a critical role in enhancing soil carbon stabilization, particularly in nitrogen-limited subsoils.
- Integrating legumes into perennial cropping systems is vital for improving productivity and soil carbon sequestration efficiency, especially with reduced nitrogen fertilizer inputs.
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