New Zealand Journal of Crop and Horticultural Science abstracts
What is a correct plant density for transplanted green asparagus?
W. T. BUSSELL
Department of Landscape & Plant Science
UNITEC Institute of Technology
Private Bag 92 025
Auckland, New Zealand
J. H. MAINDONALD
Statistics Department
University of Newcastle
Callaghan, NSW 2308, Australia
J. R. MORTON
Pacific Regional Agricultural Programme
Private Mail Bag
Suva, Fiji
Abstract We demonstrate a quantitative framework for the
study of yield-density relationships of transplanted green asparagus
(Asparagus officinalis L.). Such a framework is essential if new
research is to make effective use of what is already known. We used quadratic
equations to analyse data from 15 yield-density studies with transplanted
asparagus, in order to get indications of appropriate densities for new
plantings in New Zealand and Western Samoa. In all instances the optimum
density was close to or above the highest density used in the trial, so that
optima were often poorly defined. We work with the density which gives 90% of
the estimated optimum yield, which for practical application may be more
realistic than the density which gives optimum yield. We give details of the
methodology used for these estimates. Estimates of this 90% optimum, based on
the cumulated yields over the first 3 years, varied from 8500 to 66 000
plants/ha. The optimum planting density estimated from cumulated yields to Year
3 gave an accurate estimate of optimum planting densities for cumulated yields
to Year 7, and were substantially better for this purpose than cumulated yields
to Year 2. No clear picture emerges of factors which may affect the optimum
plant density for transplanted green asparagus, which clearly varies widely.
There are too many factors which vary in an unsystematic manner between the
different studies which we describe, or for which no information is given. We
highlight deficiencies in trial planning and/or reporting which compromise the
attempt to place individual trial results within a wider context. We make
proposals for the conduct and reporting of future studies, which if followed
will make the systematic overview of future trials more straightforward and
productive.
Keywords Asparagus officinalis; plant density; green
asparagus; transplanted; saleable yield; yield-density relationships;
systematic review
New Zealand Journal of Crop and Horticultural Science, 1997, Vol. 25:
359-368
0114-0671/97/2504-0359 $7.00/0 (c) The Royal Society of New Zealand
1997
PDF file of entire paper: medium quality (730K); (scanned from paper original: notes about this process)
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