Field experiments comparing winter and spring applications of ammonium sulphate, ammonium nitrate, calcium nitrate and urea to grassland
Devtne, J.R.; Holmes, M.R.J.
J Agr Sci 64(1): 101-107
1965
DOI: 10.1017/s0021859600010534
Accession: 014479457
Fourteen experiments were carried out in various parts of England to compare ammonium sulphate, ammonium nitrate, calcium nitrate and urea applied to grassland in early winter, late winter and spring at rates supplying 40 and 80 lb./acre of nitrogen. Yield of herbage and of nitrogen were recorded at one cut in spring. Each increment of applied nitrogen increased yield in every experiment. In all the experiments early-winter application gave lower yields than late-winter or spring application, and this inferiority was greater where the winter rainfall was high; calcium nitrate gave lower yields than the other sources when applied in early winter, especially with high rainfall. Late-winter application gave higher yields than spring application in some experiments and lower yields in others. The relative effect of the four nitrogen fertilizers was the same at these times of application; on average urea gave lower yields than the other three when applied in either late winter or early spring.