『Abstract
Mobilization of nutrients and dissolution of minerals are of
key importance for plant growth and soil formation, as well as
long term ecosystem sustainability. The effects of Pinus sylvestris
seedlings, ectomycorrhizal colonisation and potassium supply on
the mobilisation of Al, Fe, K and Si were studied in a soil column
experiment. Budgets were constructed considering amounts in drainage
water, accumulation in plants and changes in the pools of exchangeable
ions (BaCl2 extractions). Drainage was the
most important sink under the experimental conditions imposed,
but the other two pools were also of quantitative significance.
Plants had a significant positive effect on the total quantities
of all elements mobilized. Mycorrhizal colonisation had limited
quantitative impact on the mobilization, probably because the
chosen mycorrhizal fungi did not cause any growth promotion in
this experiment. Despite this, a multivariate analysis (PCA) showed
a clear separate grouping of mycorrhizal, non-mycorrhizal and
no-plant treatments, and in particular Si and K mobilization was
related to soil biological variables which in turn were affected
by the presence of mycorrhiza. When K was omitted from the watering
solution, plants were able to mobilise significantly more K, which
was reflected in plant uptake and a potential replenishment of
the exchangeable pool. Up-scaling of total Al, K and Si mobilization
to field conditions resulted in rates between equal to and up
to 10 times higher than the average historical weathering rate.
Keywords: Aluminum; Ectomycorrhiza; Mobilization; Pinus sylvestris;
Potassium; Soil』
1. Introduction
2. Materials and methods
2.1. Soil sampling and pretreatment
2.2. Plant and mycorrhizal preculture
2.3. Soil column system and growth conditions
2.4. Experimental design
2.5. Analysis of drainage water, soil and plant material
2.6. Estimation of soil weathering rate under field conditions
2.7. Calculations and statistics
3. Results
3.1. Plant growth, tissue concentrations, glucosamine concentration
in soil and pH
3.2. Uptake of Al, Fe, K and Si in plants
3.3. Cumulative amounts of Al, Fe, K and Si in drainage water
3.4. Exchangeable amounts of Al, Fe, K and Si
3.5. Total mobilization of Al, Fe, K and Si
4. Discussion
4.1. Experimental conditions and design
4.2. Plant growth and tissue concentrations
4.3. Biogeochemical cycling of Al, Fe and Si
4.4. Mobilization of K in relation to K nutrition
4.5. Assessment in relation to field conditions - impact of plants
and ectomycorrhiza
5. Conclusions
Acknowledgements
References