The effect of hydraulic lift on organic matter decomposition, soil nitrogen cycling, and nitrogen acquisition by a grass species
| Autor: | Cristina Armas, Robert B. Jackson, John H. Kim, Timothy M. Bleby |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Nutrient cycle
Nitrogen Biology Poaceae Photosynthesis Soil Animal science Nutrient Ammonia Organic matter Biomass Hydraulic redistribution Nitrogen cycle Ecology Evolution Behavior and Systematics chemistry.chemical_classification Nitrates Nitrogen Isotopes Water food and beverages Soil chemistry Biological Transport Mineralization (soil science) Nitrogen Cycle Plant Leaves Agronomy chemistry |
| Zdroj: | Oecologia. 168:11-22 |
| ISSN: | 1432-1939 0029-8549 |
| DOI: | 10.1007/s00442-011-2065-2 |
| Popis: | Hydraulic lift (HL) is the passive movement of water through plant roots, driven by gradients in water potential. The greater soil–water availability resulting from HL may in principle lead to higher plant nutrient uptake, but the evidence for this hypothesis is not universally supported by current experiments. We grew a grass species common in North America in two-layer pots with three treatments: (1) the lower layer watered, the upper one unwatered (HL), (2) both layers watered (W), and (3) the lower layer watered, the upper one unwatered, but with continuous light 24 h a day to limit HL (no-HL). We inserted ingrowth cores filled with enriched-nitrogen organic matter (15N-OM) in the upper layer and tested whether decomposition, mineralization and uptake of 15N were higher in plants performing HL than in plants without HL. Soils in the upper layer were significantly wetter in the HL treatment than in the no-HL treatment. Decomposition rates were similar in the W and HL treatments and lower in no-HL. On average, the concentration of NH4 +-N in ingrowth cores was highest in the W treatment, and NO3 −-N concentrations were highest in the no-HL treatment, with HL having intermediate values for both, suggesting differential mineralization of organic N among treatments. Aboveground biomass, leaf 15N contents and the 15N uptake in aboveground tissues were higher in W and HL than in no-HL, indicating higher nutrient uptake and improved N status of plants performing HL. However, there were no differences in total root nitrogen content or 15N uptake by roots, indicating that HL affected plant allocation of acquired N to photosynthetic tissues. Our evidence for the role of HL in organic matter decomposition and nutrient cycling suggests that HL could have positive effects on plant nutrient dynamics and nutrient turnover. |
| Databáze: | OpenAIRE |
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