0023-6152

AA00697606

16111

査読無

0023-6152

AA00697606

In two different soils, high fertility Kasuya soil and low fertility Futsukaichi soil, both have a fertilization history of low level application using organic manures and fertilizers. In 2007, a pot experiment was conducted in a greenhouse using rice variety Manawthuka to investigate the effect of higher level applications. Cow manure (CM) and poultry manure (PM) were applied as organic nitrogen sources with three levels; 15, 30 and 45 ton $ha^-1$ as low, middle and high level for CM and 3, 6 and 9 ton $ha^-1$ for PM, respectively. The manure application rates were decided by the estimation of available N by the calculation. Same rank of application level provided nearly the same available N amount. In every manure application, 20 kg urea $ha^-1$ was applied at basal. Urea fertilizer application at the rate of 50 kg N $ha^-1$ (UF) and Japanese standard fertilizer application for rice at the rate of 85:54:85 kg $ha^-1$ of N:$P_2$$O_5$:$K_2$O (J-std) were included. In UF and J-std, three times of split application were carried out at basal, active tillering and panicle initiation stage. Growth characteristics (SPAD value, tiller number and plant height) were recorded during the cultivation period. Dry matter, seed yield and nitrogen (N) uptake were significantly greater in PM compared to CM and the highest in J-std, however no significant different was observed among the levels of CM. Apparent N recovery was higher in PM compared to CM due to the higher readily available nutrient content and larger major nutrient content of PM. In both soils, the efficiency of CM was very low for the nutrition of rice and only CM application is difficult to get the optimal rice yield by short-term.