Effeciency of Mineral Nitrogen Fertilization on Yield and Botanical Composition of Grassland III. The Effect of Mineral Nitrogen Fertilization on Botanical Composition of Grassland

무기태 질소시비가 초지의 수량과 식생구성에 미치는 영향 III. 무기태 질소시비가 초지의 식생구성에 미치는 영향

This experiment was carried out to study the effect of pure nitrogen fertilization on botanical composition of grassland in 1987~ 1988 under practical conditions at the " Federal Institute for Agriculture in the Alps" in Austria. The application rates were 0, 30, 60, 90 and 120kg/ha/cut, the cutting regimes 3-, 4 , 5- and 6-cuts/year. The results were as follows: 1. Only PK fertilization resulted in higher botanical composition of Trifolium repens among legumes in grassland, which was increased by cutting frequency .2. Nitrogen fertilization on three-cut areas resulted in higher existence of generally valuable tall grasses such as Arrhenotherum elatius Trisetum flavescens and Dactylis glomerata . On the other hand, nitrogen fertilization on four-, five- and six-cut areas showed mainly Doctylis glomerato and Poa pratensis appearance. 3.For some cases, appearance of less valuable grasses, herbs and weeds such as Agropyron repens, Poa trivialis, Poa annua, Setoria viridis, Aegopodium podagra rio, Men landrium rubrum, Taraxacum officlnale, Achillea millefolium, Rorippa sylvestris and Polygonum ocleulare was *Bundesanstalt fur alpenlandische Landwirtschaft Gumpenstein(A-8952 Irdning, 6sterreich) increased on medium and high rates of N fertilized areas. 4.Reduction of sward density may also diminish the advantages of nitrogen fertilization and may be threatened by mainly high dressings of nitrogen combined with too late utilization of the sward. 5.Location altered the efficiency of nitrogen fertilization on botanical composition.mposition.