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The relationship between crop yield (or mean plant weight) of lettuce and plant density, length of growing period, and initial plant weight

Published online by Cambridge University Press:  27 March 2009

M. A. Scaife  and
D. Jones
M. A. Scaife
Affiliation:
National Vegetable Research Station, Wellesbourne, Warwicks CV35 9EF
D. Jones
Affiliation:
National Vegetable Research Station, Wellesbourne, Warwicks CV35 9EF
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Summary

Lettuce obeys the Shinozaki–Kira relationship in which the reciprocal of plant weight is linearly related to plant density. The intercept (a) represents the reciprocal of the weight of an isolated plant and the slope (b) represents the reciprocal of yield/unit area at high densities (the ‘ceiling yield’). This work examines the time course of (a) and (b) in an ‘ideal environment’ in which water and nutrients are non-limiting, and the light/temperature regime is constant.

Two pot experiments are described: the first showed that the growth of isolated lettuces follows a logistic expression, which can therefore be substituted for a–1 in the Shinozaki-Kira equation. It was then hypothesized that b–1, the ‘ceiling yield’ would be constant over time. This was confirmed by the second experiment, giving the equation

w–1t = w–10 e1–kt × w–1max × bd,

in which wt is mean plant weight at time t, w0 and wmax are the initial and final weights of isolated plants, k is the early relative growth rate of such plants, b–1 is the constant ceiling yield, and d is the plant density.

Two examples of the use of the equation are given: one shows how it predicts the interaction between seed size and plant density within a species (subterranean clover): the other illustrates how it can be used to explain why lettuce growth appears to be log-linear against time whereas cereal growth is more nearly just linear.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 86 , Issue 1 , February 1976 , pp. 83 - 91
Copyright
Copyright © Cambridge University Press 1976

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References

REFERENCES

Aspinall, D. & Milthorpe, F. L. (1959). An analysis of competition between barley and white persicaria. I. The effects on growth. Annals of Applied Biology 47, 156–72.CrossRefGoogle Scholar
Black, J. N. (1957). Seed size as a factor in the growth of subterranean clover (Trifolium subterraneum L.) under spaced and sward conditions. Australian Journal of Agricultural Research 8, 335–51.CrossRefGoogle Scholar
Blackman, V. H. (1919). The compound interest law and plant growth. Annals of Botany 33, 353–60.CrossRefGoogle Scholar
Bleasdale, J. K. A. (1966). Plant growth and crop yield. Annals of Applied Biology 57, 173–82.CrossRefGoogle Scholar
Donald, C. M. (1951). Competition among pasture plants. I. Intra-specific competition among annual pasture plants. Australian Journal of Agricultural Research 2, 355–76.CrossRefGoogle Scholar
Donald, C. M. (1963). Competition among crop and pasture plants. Advances in Agronomy 15, 1–118.CrossRefGoogle Scholar
Hewson, R. T. & Roberts, H. A. (1973). Some effects of weed competition on the growth of onions. Journal of Horticultural Science 48, 51–7.CrossRefGoogle Scholar
Jones, L. H. (1967). Factors affecting the productivity of dwarf french beans. Agricultural Progress 42, 32–52.Google Scholar
McCree, K. J. (1969). An equation for the rate of respiration of white clover plants grown in controlled conditions. In Prediction and Measurement of Photosynthetic Productivity, Proc. IBP/PP Technical Meeting, Trebon, 1969, pp. 221–9.Google Scholar
Richards, F. J. (1969). The quantitative analysis of growth. In Plant Physiology, vol. VA (ed. Steward, F. C.), 3–76. New York: Academic Press.Google Scholar
Robson, M. J. (1973). The growth and development of simulated swards of perennial ryegrass. I. Leaf growth and dry weight changes as related to the ceiling yield of a seedling sward. Annals of Botany 37, 487–500.CrossRefGoogle Scholar
Sale, P. J. M. (1966). The response of summer lettuce to irrigation and spacing. Journal of Horticultural Science, 41, 31–42.CrossRefGoogle Scholar
Scaife, M. A. (1973). The early relative growth rates of six lettuce cultivars as affected by temperature. Annals of Applied Biology 74, 119–28.CrossRefGoogle Scholar
Shinozaki, K. & Kira, T. (1956). Intraspecific competition among higher plants. 7. Logistic theory of the C-D effect. Journal of the Institute of Polytechnics, Osaka City University D7, 36–72.Google Scholar
Willey, R. W. & Heath, S. B. (1969). The quantitative relationship between plant production and crop yield. Advances in Agronomy 21, 281–321.CrossRefGoogle Scholar