New Zealand Journal of Agricultural Research abstracts
Effect of different forage plants on denitrification potential of
Horotiu soil
J. R. CRUSH
AgResearch
Ruakura Agricultural Research Centre
Private Bag 3123
Hamilton, New Zealand
Abstract Denitrification potential (DNP), water-soluble soil
carbon, soil nitrate, and plant weights were measured in lysimeters growing
cocksfoot, tall fescue, chicory, Yatsyn ryegrass, or Ruanui ryegrass in a New
Zealand soil. The soil-related parameters were measured in the topsoil and
upper- and lower-subsoil zones of the lysimeters. Significantly lower rates of
DNP were measured under Ruanui ryegrass than under the other plants and there
was a tendency for higher rates of DNP to be associated with bigger root
masses. Water-soluble carbon was higher in the topsoil than in the upper- or
lower-subsoil, but soluble carbon did not differ significantly among the
cultivars. DNP responded positively to addition of glucose to the soil,
demonstrating that soluble carbon rather than the resident populations of
denitrifying micro-organisms were limiting DNP. Lysimeters growing cocksfoot
had the lowest soil nitrate levels and the largest root systems but only
intermediate rates of DNP. The quality of root residues entering the soil under
cocksfoot is probably lower than for the other plants.
Keywords carbon; chicory; cocksfoot; tall fescue;
denitrification; nitrate; roots; rooting depth; ryegrass; soil
New Zealand Journal of Agricultural Research, 1998, Vol. 41: 421-426
0028-8233/98/4103-0421 $7.00/0 (c) The Royal Society of New Zealand
1998
PDF file of entire paper: medium quality (528K); (scanned from paper original: notes about this process)
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