The effect of different nitrogenous fertilizers, applied as solids or solutions, on the yield and nitrate-N content of established grass and newly sown ryegrass

Extract

Experiments on permanent grass and newly sown Italian ryegrass compared ammonium hydroxide solution, with ammonium sulphate, ammonium nitrate, calcium nitrate and urea, applied at 56 and 112 lb. N/acre as solids, and also when dissolved in water to give a final N content of 5 %. Ammonium hydroxide solution containing 5% N damaged established grass severely and did not increase drymatter yields; when applied to the seed-bed before sowing Italian ryegrass, ammonium hydroxide solution did not affect germination but yields were lower than with other N fertilizers.

On permanent grass all fertilizers significantly increased dry-matter yields and N uptake at both cuts. The form of N fertilizer did not significantly affect dry-matter yields or N uptake of grass of the first cut. The method of application (i.e. solid or liquid) did not affect dry-matter yields, except that ammonium nitrate in solution gave a significantly higher yield than did the solid form at the second cut; the grass had higher N content with solid forms than with solutions. The grass took up more N from solid forms than from solutions except with ammonium nitrate at the second cut. Delaying the N application by 20 days decreased dry-matter yields considerably and increased the N content of the grass.