The effect of nitrogenous fertilizer on the photosynthesis of leaves of a ryegrass sward

The addition of nitrogenous fertilizer to a newly cut, N‐deficient ryegrass sward resulted in an increased photosynthetic capacity in the next leaf to expand, showing that greater photosynthesis per unit leaf area as well as greater leaf area contributes to the increased growth of fertilized swards. Later in the 4‐week growth period there was little difference in photosynthetic capacity between fertilized and unfertilized swards.