THE USE OF NITROGENOUS FERTILIZER IN THE PRODUCTION OF GRASSLAND HERBAGE

Ammonium nitrate and calcium cyanamide were applied to an orchard grass, ladino clover sward over a 3-year period. Rates to give 0, 50, 100 and 150 lb. of nitrogen per acre were applied in two ways: single spring applications, and split applications, one-half in the spring and one-half immediately following an early first cutting.Ammonium nitrate proved to be the more effective source of nitrogen whether measured by yield, crude protein of the herbage or net recovery of nitrogen.Single spring applications of nitrogenous fertilizer gave greater seasonal total yields of dry matter and crude protein and more efficient net recovery of nitrogen than did split applications.Where no nitrogen was applied there was an increase in the clover content of the sward, total yield of dry matter and the total yield of crude protein during the 3 years of the test. However, the greatest seasonal total from these plots did not equal that obtained from the highest rate of application of fertilizer nitrogen. The highest of the rates almost completely suppressed clover development but gave the greatest yields of dry matter and crude protein and the most efficient net recoveries of nitrogen.