New Zealand Journal of Agricultural Research abstracts

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Sustainability of New Zealand high-country pastures under contrasting development inputs. 6. Fertiliser efficiency

D. SCOTT

AgResearch
P.O. Box 60
Lincoln, New Zealand

Abstract  Using 15 years of grazing records from two trials with 31 different sulphur (S) and phosphorus (P) fertiliser combinations on a Tekapo/Pukaki high-country soil, the most profitable fertiliser combinations for long-term sustainable production were determined from consideration of fertiliser composition, ex-works, transport, and spreading costs, increase in sheep carrying capacities, and discount rates. In a soil with a high natural surface-soil P level, the optimum returns were determined solely by elemental-S fertiliser rates. The estimated greatest net returns from annual applications rates were at 53 kg S ha^-1 yr^-1, or between 24 and 39 kg S ha^-1 yr^-1 if ratio of return versus input was considered. Using carrying capacity response functions and elemental-S oxidation rates, it was estimated that the best long-term sustainable fertiliser strategy was for 5-yearly applications of 250 kg ha^-1 of 2.2-mm coarse-particle elemental S.

Keywords  New Zealand; high-country; S; P; economics; fertiliser; grazing; sustainability

New Zealand Journal of Agricultural Research, 2000, Vol. 43: 525-532

0028-8233/00/4304-0525 $7.00/0 (c) The Royal Society of New Zealand 2000

PDF file of entire paper: medium quality (700K); (scanned from paper original: notes about this process)

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