Effects of nitrogen and phosphorus fertilisers on yield and on inorganic and organic composition of italian ryegrass grown on phosphorus-deficient soil

✍ Scribed by Tadeusz Z. Nowakowski; Geoffrey E. G. Mattingly; William Lazarus

• Publisher: John Wiley and Sons
• Year: 1977
• Tongue: English
• Weight: 636 KB
• Volume: 28
• Category: Article
• ISSN: 0022-5142
• DOI: 10.1002/jsfa.2740280605

✦ Synopsis

Abstract

Italian ryegrass (Lolium multiflorum) S22, grown in a greenhouse in phosphorus‐deficient soil in pots was given 40 and 160 mg N/kg of soil (as ammonium nitrate) and 5, 25 and 100 mg P/kg of soil (as calcium tetrahydrogen diorthophosphate). Giving more nitrogen increased yields only when adequate phosphorus was applied. A significant response to added phosphorus was obtained when ryegrass dry matter contained about 0.15% P or less. Nitrogen increased the amount of sugars but decreased that of fructosan. Phosphorus increased the production of both sugars and fructosan. Protein N (expressed as a percentage of total N) increased with increasing amounts of phosphorus given. The largest values for protein N were obtained when grass contained about 0.3 % P in the dry matter. In phosphorus‐deficient grass nitrate‐N accumulated and the predominant compounds within the free amino acid fraction were asparagine and glutamine. Adding phosphorus decreased the concentrations of both nitrate‐N and the amides. The amino acid composition of the grass protein was not affected by the nitrogen and phosphorus treatments.