Orchardgrass 채초형초지에 있어서의 질소이용효율에 대하여 3 . 질소이용율 = Efficiency of Nitrogen Utilization under Hay - type Management in Orchardgrass Varieties 3 . Apparent N recovery

다국어 초록 (Multilingual Abstract)

This experiment was to study the efficiency of nitrogen utilization (Apparent N recovery %) under hay-type management, based on the data of preceeding paper Apparent N recovery which was expressed as precentages of absorbed N to fertilized N in excess of that in non-fertilized plot. The results are may be summarized as follows; 1. Mean apparent N revovery to the basal N fertilization levels was higher at the early heading stage than the first cutting at the end of the heading stage in all varieties. The values of the early heading stage were 46.7, 42.4 and 23.6% in Kitamidori, Latar and S143, respectively. 2. Mean values of second cutting were 65.9 (ranged from 46.4-83.7), 55.2 (41.7-75.2) and 41.3% (30.5-48.6) for Kitamidori, Latar and S143, respectively. After the middle of September, the values of apparent N recovery decreased quickly as growth progressed. 3. Mean apparent N recovery of the annual yields, the values were 52.3, 47.0 and 26.8% in Kitamidori, Latar and S143. The Kitamidori variety showed the highly significant value. 4. The highest values of apparent N recovery obtained were 71.0, 70.8 and 31.0% at the 200kg/ha per annum in Kitamidori, Latar and S143. 5. Apparent N recovery at the levels of N with the predictable highest yield, it ranges from 45.791. to 40.5% in Kitamidori, from 46.6% to 41.4% in Latar and below the 23.9% in S143.