New Zealand Journal of Agricultural Research abstracts
Uptake of moisture and nutrients by Hieracium pilosella and effects on soil in
a dry sub-humid grassland
C. C. BOSWELL
P. R. ESPIE
AgResearch
Invermay Agricultural Research Centre
Private Bag 50034
Mosgiel, New Zealand
Abstract In dry sub-humid environments (<550 mm annual
rainfall) in New Zealand, Hieracium pilosella (hawkweed) grows in
approximately circular or irregular shaped patches surrounded by areas of bare
soil. The study directly assessed the extent of root distribution, soil
moisture, and nutrient uptake in the areas of bare soil zone ("haloes")
surrounding patches, and how hawkweed affected the soil. The results indicate
that H. pilosella exploits the halo areas surrounding the plant patches
for a major part of moisture and nutrients uptake. As a result, the soil in the
halo zone is drier than that under the plant patch and is relatively depleted
in such nutrients as available phosphorus and basic cations. The plant
increases soil acidity and soluble aluminium content in the soil immediately
beneath the living patch. The combined effects of reduced moisture, reduced
base cation availability, and the high soluble aluminium status and increased
acidity of the soil, make the immediate hawkweed environment unfavourable for
the development of competing plant species.
Keywords acidity; aluminium; Hieracium
pilosella; patch formation; tussock grasslands
New Zealand Journal of Agricultural Research, 1998, Vol. 41: 251-261
0028-8233/98/4102-0251 $7.00/0 (c) The Royal Society of New Zealand
1998
PDF file of entire paper: medium quality (1849K); (scanned from paper original: notes about this process)
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