Abstract
A microcosm study was conducted outdoors at ambient temperatures in York, UK, to investigate the effects of seasonal temperature changes on NH4+-N dynamics associated with litter mineralization. Temporal variations in the effects of a surface litter layer and litter mixed with near-surface mineral soils on the mobility of NH4+-N were assessed over 7 months from the start of winter. Litter decomposition and associated N mineralization contributed significantly towards NH4+-N production in the soil profiles, especially at 0-10 cm depths, even at low winter temperatures. Increase in temperature over time substantially increased KCl-extractable and water-soluble NH4+-N concentrations via enhanced organic matter mineralization. The difference between KCl-extractable and water-soluble NH4+-N increased over time, as much of the NH4+-N produced and mobilized in the litter layer was retained in the soil profiles. Surprisingly, the presence of litter, especially in the mixed litter treatment, markedly reduced mineral-N concentrations in the leachate in winter. Nitrate-N concentrations in leachate were substantially lowered in summer too, in spite of the absence of vegetation uptake in summer. This indicates that microbial N immobilization in soil and/or abiotic N retention linked with soil organic matter, and not just plant-N uptake, reduce nitrate leaching to freshwaters in summer months. (C) 2010 Elsevier B.V. All rights reserved.
| Original language | English |
|---|---|
| Pages (from-to) | 198-208 |
| Number of pages | 11 |
| Journal | Geoderma |
| Volume | 159 |
| Issue number | 1-2 |
| DOIs | |
| Publication status | Published - 15 Oct 2010 |
Keywords
- Litter
- Mineralization
- Ammonium
- Nitrogen cycle
- DOC
- Temporal variations
- DISSOLVED ORGANIC-CARBON
- N MINERALIZATION
- NITROGEN-CYCLE
- FOREST SOILS
- DECOMPOSITION
- TEMPERATURE
- ECOSYSTEMS
- RETENTION
- MATTER
- WATER