Hostname: page-component-586b7cd67f-2brh9 Total loading time: 0 Render date: 2024-11-25T22:55:44.671Z Has data issue: false hasContentIssue false

Some mathematical aspects of the clover, grass, and fertilizer nitrogen relations

Published online by Cambridge University Press:  27 March 2009

D. A. Stewart
Affiliation:
Biometrics Division, Ministry of Agriculture, Dundonald House, Belfast 4, Northern, Ireland
D. M. B. Chestnutt
Affiliation:
Loughry Agricultural College, Cookstown, Co Tyrone, Northern, Ireland

Summary

This article attempts to discuss the relations between the nitrogen sources in data from a large field experiment in which various levels of fertilizer nitrogen were applied to various grass mixtures in the presence and absence of white clover. It was seen that a number of effects occurred, among them the strong depression of clover nitrogen by fertilizer nitrogen (to the extent that equations predicting their contribution to grass nitrogen could not be produced directly by multiple regression but had to be constructed separately), a further apparent depression of clover nitrogen transfer effectiveness, a more significant relationship between grass nitrogen increase and the previous year's clover nitrogen than the current year's clover nitrogen, and apparent competition between grass and clover despite the latter's contribution to increased grass yield.

As some of the effects are counteractive, in each comparison made a balance appears to exist. This varies between sites and years in such a way that although the variation in grass nitrogen is always largely dependent on the clover and fertilizer nitrogen the relations are not consistent as shown by the mathematical equation representing them, and cannot be extrapolated or predicted for other sites. It is suggested that a mathematical model be constructed to simulate such an interactive system and that predictions when necessary be made using this, rather than using simple equations.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1974

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Butler, G. W. & Bathturst, N. I. (1956). The underground transference of nitrogen from clover to associated grass. Proceedings of the 7th International Grassland Congress, pp. 168–78.Google Scholar
Chestnutt, D. M. B. (1970). Interaction of grass species grown alone and in mixtures in presence of white clover at various levels of applied nitrogen. Record of Agricultural Research. Ministry of Agriculture, Northern Ireland 18, 143–54.Google Scholar
Cowling, D. W., Green, J. O. & Green, S. M. (1964). The effect of white clover and nitrogenous fertilizer on the production of a sward. Journal of the British Grassland Society 19, 419–24.CrossRefGoogle Scholar
Lowe, J. (1964). Ph.D. Thesis, Faculty of Agriculture, Queen's University, Belfast. Economic evaluation of white clover Trifolium repens in grassland.Google Scholar
O'Connor, K. F. (1961). Nitrogen and Grassland Production in the mid-altitude zone of Canterbury, New Zealand. New Zealand Journal of Agricultural Research 4, 686–97.CrossRefGoogle Scholar
Peterson, M. L. & Bendixen, L. E. (1961). Plant competition in relationship to nitrogen economy. Agronomy Journal 53, 4549.CrossRefGoogle Scholar
Walker, T. W., Orchiston, H. D. & Adams, A. F. R. (1954). The nitrogen economy of grass legume association. Journal of the British Grassland Society 9, 249–74.CrossRefGoogle Scholar