초지에 대한 인산질비료의 시용에 관한 연구 IV. 인산질비료의 시용수준이 목장의 식생구성과 무기물함량 및 토양화학성분에 미치는 영향 ( Studies on the Phosphatic fertilizer Application Grassland IV. Effect of phosphatic fertilizer levals on the botanial compos

To find out the effects of phosphatic fertilizer application levels on the botanical composition, mineral contents and mineral nutrient deprivation of grasses and the chemical properties of soil, this expriment was arranged as a randomized complete block design with six treatments(0, 50, 100, 150, 200 and 250kg $P_2O_5$/ha) and conducted at hilly land in Gwangju, Gyeonggi Province from September, 1989 to October, 1992. The results obtained are summarized as follows: The botanical composition of grasses without posphatic fertilizer application was poor but with 150kg $P_2O_5$/ha application, remarkably increased in legume of grasses and decreaed in weed. As the phophatic fertilizer levels increase, P, Ca and Mg content of grasses were increased but N and K content tended not to be regular, and Ca/p and K/Ca+ Mg equivalent ratio were lowered. Up to 150kg $P_2O_5$/ha application level, the mineral nutrient content deprived by dry matter yield was increased but with that over application, tend not to be increased. Most of applied mineral elements were accumulated at a subsurface of grassland and as the phosphatic fertilizer application levels increase, the available $P_2O_5$ and exchangeable Mg contents of the soil tended to be remarkably increased and exchangeable K content tended to be decreased, but pH, OM and exchangeable Ca content tended not to be regular.