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The vertical distribution of N and K uptake in relation to root distribution and root uptake capacity in mature Quercus robur, Fagus sylvatica and Picea abies stands

Goransson, Hans; Ingerslev, Morten and Wallander, Håkan LU (2008) In Plant and Soil 306(1-2). p.129-137
Abstract
We have measured the uptake capacity of nitrogen (N) and potassium (K) from different soil depths by injecting N-15 and caesium (Cs; as an analogue to K) at 5 and 50 cm soil depth and analysing the recovery of these markers in foliage and buds. The study was performed in monocultures of 40-year-old pedunculate oak (Quercus robur), European beech (Fagus sylvatica) and Norway spruce (Picea abies (L.) Karst.) located at an experimental site in Palsgard, Denmark. The markers were injected as a solution through plastic tubes around 20 trees of each species at either 5 or 50 cm soil depth in June 2003. After 65 days foliage and buds were harvested and the concentrations of N-15 and Cs analysed. The recovery of N-15 in the foliage and buds tended... (More)
We have measured the uptake capacity of nitrogen (N) and potassium (K) from different soil depths by injecting N-15 and caesium (Cs; as an analogue to K) at 5 and 50 cm soil depth and analysing the recovery of these markers in foliage and buds. The study was performed in monocultures of 40-year-old pedunculate oak (Quercus robur), European beech (Fagus sylvatica) and Norway spruce (Picea abies (L.) Karst.) located at an experimental site in Palsgard, Denmark. The markers were injected as a solution through plastic tubes around 20 trees of each species at either 5 or 50 cm soil depth in June 2003. After 65 days foliage and buds were harvested and the concentrations of N-15 and Cs analysed. The recovery of N-15 in the foliage and buds tended to be higher from 5 than 50 cm soil depth in oak whereas they where similar in spruce and beech after compensation for differences in immobilization of N-15 in the soil. In oak more Cs was recovered from 5 than from 50 cm soil depth whereas in beech and spruce no difference could be detected. Out of the three investigated tree species, oak was found to have the lowest capacity to take up Cs at 50 cm soil depth compared to 5 cm soil depth also after compensating for differences in discrimination against Cs by the roots. The uptake capacity from 50 cm soil depth compared with 5 cm was higher than expected from the root distribution except for K in oak, which can probably be explained by a considerable overlap of the uptake zones around the roots and mycorrhizal hyphae in the topsoil. The study also shows that fine roots at different soil depths with different physiological properties can influence the nutrient uptake of trees. Estimates of fine root distribution alone may thus not reflect the nutrient uptake capacity of trees with sufficient accuracy. Our study shows that deep-rooted trees such as oak may have lower nutrient uptake capacity at deeper soil layers than more shallow-rooted trees such as spruce, as we found no evidence that deep-rooted trees obtained proportionally more nutrients from deeper soil layers. This has implications for models of nutrient cycling in forest ecosystems that use the distribution of roots as the sole criterion for predicting uptake of nutrients from different soil depths. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Oak, tree root distribution, nutrient uptake, Cs, N-15, beech, spruce
in
Plant and Soil
volume
306
issue
1-2
pages
129 - 137
publisher
Springer
external identifiers
  • wos:000254849800014
  • scopus:41949105920
ISSN
0032-079X
DOI
10.1007/s11104-007-9524-x
language
English
LU publication?
yes
id
2040e13c-ae25-481b-ae62-f73b102fa7b2 (old id 1206606)
date added to LUP
2008-08-28 14:49:53
date last changed
2017-05-07 03:47:44
@article{2040e13c-ae25-481b-ae62-f73b102fa7b2,
  abstract     = {We have measured the uptake capacity of nitrogen (N) and potassium (K) from different soil depths by injecting N-15 and caesium (Cs; as an analogue to K) at 5 and 50 cm soil depth and analysing the recovery of these markers in foliage and buds. The study was performed in monocultures of 40-year-old pedunculate oak (Quercus robur), European beech (Fagus sylvatica) and Norway spruce (Picea abies (L.) Karst.) located at an experimental site in Palsgard, Denmark. The markers were injected as a solution through plastic tubes around 20 trees of each species at either 5 or 50 cm soil depth in June 2003. After 65 days foliage and buds were harvested and the concentrations of N-15 and Cs analysed. The recovery of N-15 in the foliage and buds tended to be higher from 5 than 50 cm soil depth in oak whereas they where similar in spruce and beech after compensation for differences in immobilization of N-15 in the soil. In oak more Cs was recovered from 5 than from 50 cm soil depth whereas in beech and spruce no difference could be detected. Out of the three investigated tree species, oak was found to have the lowest capacity to take up Cs at 50 cm soil depth compared to 5 cm soil depth also after compensating for differences in discrimination against Cs by the roots. The uptake capacity from 50 cm soil depth compared with 5 cm was higher than expected from the root distribution except for K in oak, which can probably be explained by a considerable overlap of the uptake zones around the roots and mycorrhizal hyphae in the topsoil. The study also shows that fine roots at different soil depths with different physiological properties can influence the nutrient uptake of trees. Estimates of fine root distribution alone may thus not reflect the nutrient uptake capacity of trees with sufficient accuracy. Our study shows that deep-rooted trees such as oak may have lower nutrient uptake capacity at deeper soil layers than more shallow-rooted trees such as spruce, as we found no evidence that deep-rooted trees obtained proportionally more nutrients from deeper soil layers. This has implications for models of nutrient cycling in forest ecosystems that use the distribution of roots as the sole criterion for predicting uptake of nutrients from different soil depths.},
  author       = {Goransson, Hans and Ingerslev, Morten and Wallander, Håkan},
  issn         = {0032-079X},
  keyword      = {Oak,tree root distribution,nutrient uptake,Cs,N-15,beech,spruce},
  language     = {eng},
  number       = {1-2},
  pages        = {129--137},
  publisher    = {Springer},
  series       = {Plant and Soil},
  title        = {The vertical distribution of N and K uptake in relation to root distribution and root uptake capacity in mature Quercus robur, Fagus sylvatica and Picea abies stands},
  url          = {http://dx.doi.org/10.1007/s11104-007-9524-x},
  volume       = {306},
  year         = {2008},
}