Hostname: page-component-586b7cd67f-dlnhk Total loading time: 0 Render date: 2024-11-30T16:53:38.945Z Has data issue: false hasContentIssue false

The effect on yield and leaf area of wheat of applying nitrogen as a top-dressing in April or in sprays at ear emergence

Published online by Cambridge University Press:  27 March 2009

Gillian N. Thorne
Affiliation:
Rothamsted Experimental Station, Harpenden, Herts.
D. J. Watson
Affiliation:
Rothamsted Experimental Station, Harpenden, Herts.

Extract

Nitrogen, at the rate of 0.5 cwt./acre, was applied to winter wheat as an April dressing of nitrochalk, or as eight sprayings of 2% NH4NO3 solution applied either to the soil or to the leaves at about the period of maximum leaf area, before and during ear emergence. All three methods of nitrogen application caused similar increases in yield and nitrogen content of grain. April nitrogen gave a greater yield of straw than the later dressings.

Late nitrogen application caused a small increase in leaf area index, first noticeable one week after ear emergence and persisting for another four weeks. L.A.I. of plots that received nitrogen in April was much larger than that of the other plots at the period of maximum leaf area, but by four weeks after ear emergence it was less than that of plots receiving the late nitrogen. Shoot number per metre and leaf area per shoot were increased by early nitrogen, but only the latter was increased by nitrogen applied at ear emergence.

Leaf area duration after ear emergence was the same on all nitrogen-treated plots and the yield of grain divided by L.A.D. was nearly constant for all plots.

Applying nitrogen late, after an April dressing, did not prevent the rapid fall in L.A.I. from the high value reached at the period of maximum leaf area and caused no greater increase in yield than when applied in the absence of an April top-dressing. A single urea spray applied in early June increased yield to the same extent as the ammonium nitrate sprays.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1955

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

REFERENCES

Asana, R. D. & Mani, V. S. (1950). Physiol. Plant. 3, 22.CrossRefGoogle Scholar
Bald, J. G. (1943). Phytopathology. 33, 922.Google Scholar
Boonstra, A. E. H. R. (1929). Meded LandbHoogesch., Wageningen, 33, 3.Google Scholar
Jealott's Hill Research Station (1953). Guide to Field Experiments, p. 50.Google Scholar
Knowles, F. & Watkin, J. E. (1931). J. Agric. Sci. 21, 612.Google Scholar
Lewis, A. H., Procter, J. & Trevains, D. (1938). J. Agric. Sci. 28, 618.CrossRefGoogle Scholar
Low, A. J. & Armitage, E. R. (1954). Agriculture, 61, 368.Google Scholar
Porter, H. K., Pal, N. & Martin, R. V. (1950). Ann. Bot., Lond., N.S. 14, 55.Google Scholar
Salt, G. A. (1953). Ph.D. Thesis, University of London.Google Scholar
Smith, H. F. (1933). J. Counc. Sci. Industr. Res. Aust. 6, 32.Google Scholar
Thorne, G. N. (1955). J. Exp. Bot. 6, 20.Google Scholar
Thorne, G. N. & Watson, D. J. (1956). J. Agric. Sci. (in the Press).Google Scholar
Watson, D. J. (1937). J. Agric. Sci. 27, 474.Google Scholar
Watson, D. J. (1939). J. Agric. Sci. 29, 379.Google Scholar
Watson, D. J. (1947). Ann. Bot., Lond., N.S. 11, 41.CrossRefGoogle Scholar
Watson, D. J. (1952). Advanc. Agron. 4, 101.CrossRefGoogle Scholar
Williams, R. F. (1954). Aust. J. Agric. Res. 5, 235.CrossRefGoogle Scholar