The Effects of Nitrogen Fertilization Levels on the Content of ${NH_4}^+$-N and ${NO_3}^-$-N in Soil of Zoysiagrass(Zoysia japonica ) and 'Suffolk' Kentucky Bluegrass(Poa pratensis)

한국잔디(Zoysia japonica)와 'Suffolk' Kentucky bluegrass(poa pratensis)에서 지소지용 수준이 토양중 ${NH_4}^+$-N와 ${NO_3}^-$-N 함량에 미치는 영향

This experiment was conducted to investigate the effect of the nitrogen fertilization levels on the content of $NH_4^+$-N in soil of 'Suffolk' Kentucky bluegrass and zoysiagrass. The results obtained are summarized as follows : 1.According to the nitrogen fertilization levels, the content of $NH_4^+$-N in soil of Kentucky blue-grass and zoysiagrass was not significantly different. The content of $NH_4^+$-N in soil of Kentucky bluegrass and zoysiagrass was highest in June and December and lowest in March and September. 2.The content of $NH_3^-$-N in soil was increased by increasing the nitrogen fertilization levels in both Kentucky bluegrass and zoysiagrass. However, the deeper the depth of soil the less the content of $NO_3^-$-N in soil. In 40~60cm soil depth, the content of $NO_3^-$-N in soil was lower than 10ppm in average. Even in June, which was the highest month of the content of $NO_3^-$-N in soil, the content of $NO_3^-$-N in soil was not overpassed the degree of 20ppm.