Hostname: page-component-7479d7b7d-68ccn Total loading time: 0 Render date: 2024-07-13T15:46:35.429Z Has data issue: false hasContentIssue false

Results from an experiment on permanent grass evaluating the cumulative effects of aqueous urea, injected alone or with a nitrification inhibitor, with those of ‘Nitro-Chalk’

Published online by Cambridge University Press:  27 March 2009

J. Ashworth
Affiliation:
Rothamsted Experimental Station, Harpenden, Herts, AL5 2JQ
F. V. Widdowson
Affiliation:
Rothamsted Experimental Station, Harpenden, Herts, AL5 2JQ
A. Penny
Affiliation:
Rothamsted Experimental Station, Harpenden, Herts, AL5 2JQ
A. J. Gibbs
Affiliation:
Rothamsted Experimental Station, Harpenden, Herts, AL5 2JQ
R. A. Hodgkinson
Affiliation:
Rothamsted Experimental Station, Harpenden, Herts, AL5 2JQ
M. V. Hewitt
Affiliation:
Rothamsted Experimental Station, Harpenden, Herts, AL5 2JQ

Summary

In an experiment on permanent grass at Rothamsted during 1975–9 fertilizer-N was applied each year either by injecting an aqueous solution of urea (supplying 250, 375 or 500 kg N/ha) in spring, or by broadcasting ‘Nitro-Chalk’ granules (supplying 100, 200, 300, 400 or 500 kg N/ha) in six equal dressings for each of six cuts.

Dry-matter production was largest on plots injected with urea through knives 30 cm apart, and more N was recovered from the injected than from the broadcast applications. Aqueous urea injected at the 60 cm knife spacing nitrified more slowly and persisted in the soil longer than urea injected at 30 cm spacing; this persistence caused grass to grow more uniformly throughout the season, but yields were less. Injecting the nitrification inhibitor sodium trithiocarbonate (STC) with the aqueous urea postponed N uptake much less than doubling knife spacing, but the inhibitor substantially diminished percentage N03-N in harvested grass.

In spring 1977 individual plots were split to measure N residues. Half-plots thus received N at the specified rates, either in 4 successive years (1975–8) or in two pairs of successive years (1975 and 1976; 1978 and 1979). In 1977 urea injected in the 2 previous years gave large residual effects, which were increased by STC and also by injecting in bands 60 instead of 30 cm apart. Broadcast ‘Nitro-Chalk’ had much smaller residual effects. In 1979 residual effects of N applied in the 4 previous years were apparently small, regardless of the method of application, because clover became abundant on plots not given N.

In 1978 dry-matter production was smaller where N had been given each year during 1975–8 than where N was withheld in 1977. Analysis showed this was caused by a shortage of potassium. This effect was most pronounced where 375 or 500 kg N/ha had been injected in bands 60 cm apart.

The results showed that a single, injected application of aqueous urea increased yields of dry grass as effectively as equivalent repeated dressings of ‘Nitro-Chalk’.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1982

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

Ashworth, J., Briggs, G. G., Evans, A. A. & Matula, J. (1977). Inhibition of nitrification by nitrapyrin, carbon disulphide and trithiocarbonate. Journal of the Science of Food and Agriculture 28, 673683.CrossRefGoogle Scholar
Ashworth, J. & Flint, R. C. (1974). Delayed nitrification and controlled recovery of aqueous ammonia injected under grass. Journal of Agricultural Science, Cambridge 83, 327333.CrossRefGoogle Scholar
Ashworth, J., Gibbs, A. J., Hewitt, M. V., Penny, A. & Widdowson, F. V. (1979). Aqueous N fertilizers and nitrification inhibitors for grass. Rothamsted Experimental Station, Report for 1978, Part 1, p. 277.Google Scholar
Ashworth, J., Penny, A., Widdowson, F. V. & Briggs, G. G. (1980). The effects of injecting nitrapyrin (‘N-Serve’), carbon disulphide or trithiocarbonates, with aqueous ammonia, on yield and %N of grass. Journal of the Science of Food and Agriculture 31, 229237.CrossRefGoogle Scholar
Hodgson, J. M. (1967). Soils of the West Sussex Coastal Plain. Bulletin of the Soil Survey of Great Britain.Google Scholar
Litchfield, M. H. (1967). The automated analysis of nitrite and nitrate in blood. Analyst, London 92, 132136.CrossRefGoogle ScholarPubMed
Nowakowski, T. Z., Ashworth, J. & Lazarus, W. (1977). Effects of nitrification inhibitors on the composition of permanent grass. Rothamsted Experimental Station, Report for 1976, Part 1, p. 85.Google Scholar
Penny, A., Widdowson, F. V. & Ashworth, J. (1977). Results from an experiment on permanent grass evaluating aqueous ammonia and aqueous urea, injected in bands either 30 or 60 cm apart. Journal of Agricultural Science, Cambridge 88, 319331.CrossRefGoogle Scholar
Varley, J. A. (1966). Automatic methods for the determination of nitrogen, phosphorus and potassium in plant material. Analyst, London 91, 119126.CrossRefGoogle Scholar
Welbank, P. J., Gibb, M. J., Taylor, P. J. & Williams, E. D. (1974). Root growth of cereal crops. Rothamsted Experimental Station, Report for 1973, Part 2, pp. 2666.Google Scholar
Widdowson, F. V., Penny, A. & Flint, R. C. (1972). Results from an experiment comparing aqueousammonia with ‘Nitro-Chalk’ for grazed grass. Journal of Agricultural Science, Cambridge 79, 341348.CrossRefGoogle Scholar
Widdowson, F. V., Penny, A. & Flint, R. C. (1973). Results from experiments comparing aqueous and anhydrous ammonia with ‘Nitro-Chalk’ for grass cut for silage. Journal of Agricultural Science, Cambridge 81, 465480.CrossRefGoogle Scholar