Effects of nitrogen and phosphorus fertilizer application on seasonal changes in dry matter production of Tall fescue (Festuca arundinacea Schr.) cultivated on sand medium

Abstract

Effects of nitrogen and phosphorus treatment at various levels on seasonal changes in dry matter production of tall fescue (Festuca arundinacea Schr.), which was cultivated on sand medium, were investigated. The results obtained were as follows ;
1) Top growth rate had two peaks in late July and early September. The values on the peaks increased according to nitrogen level.
2) Leaf area index and top dry weight showed the highest value at the highest nitrogen level plot (N40), which showed a large seasonal change and a decrease in summer. On the other hand, the highest phosphorus level plot (P32) did not show a decrease in summer.
3) Root surface area and root dry weight became higher with higher phosphorus level, conversely lower with higher nitrogen levels.Especially, the highest nitrogen level plot (N40) did not show the root growth in summer.Regarding R-T ratio, N40 plot showed a low value but the other plots showed increase from summer to autumn.
4) Shoot density was tend to decrease with increasing nitrogen level but increase with phosphorus level.
These results showed that the nitrogen application at high level increased only the top dry matter production of tall fescue and intensely decreased R/T ratio in summer season, on the other hand, the phosphorus application at high level increased the root dry matter production in summer season and maintained high shoot density through warm season.