The Influence of Two Levels of Nitrogenous Fertilizing on the Long‐term Productivity of Leys

Abstract

Two levels of nitrogen application (70 and 180 lb per acre per annum) were compared on 6 long-duration leys. The treatments were repeated for periods of up to 4 years on tiie same swards. The higher N dressing produced 2230 Ib more dry matter per acre than the low rate, an increase of 28",,, and the yield was also more evenly spread throughout the season. There was virtually no clover on the high-N swards. The proportion of clover varied under low N but tended to increase as the season progressed. The sown grasses remained the dominant sward constituents throughout the experiment, and there was no sign of loss of vigour on the high-N swards. Utilized-starch-equivalent outputs were calculated from 3 different swards for 1956-8 and there was a significant positive correlation between the dry-matter yields and utilized-starch-equivalent output of swards.

Effect of Topdressed Nitrogen and Potassium on the Feeding Value of Orchardgrass Hay for Lactating Dairy Cows1

“…When the yields were calculated as crude protein based upon the perecentages given in Table 4 the yield responses were even more striking except with the 2NPK hay. The yield increases of dry matter and crude protein substantiate findings of other workers (2,15,21).…”

“…Nitrogen fertilizer has been shown by many investigators to increase yields of forage (1,2,15,21). In addition, the use of nitrogen fertilizer on forage has significantly increased the crude protein content of grasses (3,5,13,15,18,21).…”