Document: FEI-3-60-12

Calcium uptake from different soil depths explains chemical differences between surface soils under sugar maple or ash and under hemlock.

DIJKSTRA, F.*

Wageningen University, Wageningen 6700 AA The Netherlands ¹

Abstract:
Surface soils under either sugar maple or ash had significantly higher soil pH and available calcium than those under hemlock. Trees could affect the pool of available calcium from deeper soil layers through uptake of calcium by deep roots and bringing it back to the surface in litterfall, followed by calcium mineralization. To test the importance of this mechanism, a simple calcium budget was made for sites with different tree species. Atmospheric input of calcium was measured with bulk deposition collectors and calcium weathering in the soil was investigated by using strontium isotopes. Calcium leaching at 20 cm was calculated by combining modeled hydrology with measured calcium soil solution concentration at 20 cm depth. The strontium isotope study showed that calcium weathering in the first 20 cm of the soil was not as much influenced by tree species as by the parent material of the soil. However, calcium leaching at 20 cm depth appeared much higher for sugar maple and white ash than for hemlock. The calcium budgets suggested that the deep rooting species sugar maple and white ash take up significant amounts of calcium from deep soil layers below 20 cm. The shallow rooting hemlock takes up little calcium from deeper soil layers and the calcium that is leached out below the rooting zone is lost permanently. Over time, pumping could be an important mechanism for trees with deep root systems to sustain high levels of available calcium in the surface soil.

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This abstract is being presented at: 10:15 AM in session:
Oral Session #61: Plant Responses to Nutrients.