New Zealand Journal of Agricultural Research abstracts
Pasture establishment and fertiliser requirements on rehabilitated land after
opencast coal mining in New Zealand
R. D. LONGHURST
M. B. O'CONNOR
AgResearch
Ruakura Agricultural Centre
Private Bag 3123
Hamilton, New Zealand
M. R. J. TOXOPEUS
40 Levers Rd
Matua
Tauranga, New Zealand
Abstract Existing pasture establishment practices to
rehabilitate land after opencast mining in the Waikato coal fields area of New
Zealand were examined and compared with an alternative method involving
different pasture mixtures, seeding rates, and lime and fertiliser
requirements. Pasture establishment and production, botanical composition
changes, and plant and soil nutrient status were measured during a 2-year field
trial. Highly significant pasture responses were obtained to increased
fertiliser inputs. Heavy rates of fertiliser (1000 kg ha-1
superphosphate) were required to raise Olsen P soil levels during the
establishment phase whereas half that rate was found to be sufficient for the
maintenance phase. An improved seed mixture, containing superior pasture
cultivars, established more quickly and out-yielded the existing seed mixture
by 58%. The two seed mixtures responded differently to sowing rates; the higher
rate increased pasture yields of the improved pasture species but decreased the
existing seed mix yields. Liming at 5 t ha-1 significantly increased
soil pH and clover content and reduced pasture manganese concentrations from
possibly toxic levels. Nitrogen concentrations in pastures were below optimum
throughout the trial and the strategic use of nitrogen fertiliser is
recommended as a useful management option.
Keywords land rehabilitation; land restoration; opencast
mining; pasture establishment; liming; superphosphate; nitrogen; manganese;
ryegrass
New Zealand Journal of Agricultural Research, 1999, Vol. 42: 27-36
0028-8233/99/4201-0027 $7.00/0 (c) The Royal Society of New Zealand
1999
PDF file of entire paper: medium quality (744K); (scanned from paper original: notes about this process)
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