日本作物学会紀事 60-1, 101-106 (1991)
Key words: growth, N-uptake, rice plant, slow release
fertilizer, tropics, yield
Field experiments on the response of rice plants to slow
release fertilizer (Meister 10, MS10) were conducted from the 1986 wet
season (WS) to 1987 WS at IRRI, with ammonium sulfate (AS) as control.
IR64 and IR36892-163-1-2-2-1 were planted under two N levels and three
spacing.
In all experimental plots regardless of season, the amount
of N in the plants increased exponentially t the early growth stage (y=abx)
and linearly at the middle and late growth stages (y=a+bx), as previously
reported. MS10 lengthend the exponential phase and increased parameter
'b' during the linear phase, The amount of N in the plants was higher in
AS than in MS10 plots up to 5 weeks after transplanting, Comparing narrow
and wide spacing, the difference in the amount of N in the plants was greater
in the MS10 plots. At flowering and maturity, the amount of N in the plants
was higher in the MS10 plots due to the higher percentage recovery of basal
N and the higher rate of N absorption during the linear phase. The amount
of N in the plants grown under MS10 was almost equivalent to those in the
plants grown under a double dose of basal AS.
Tillering pattern and achievement of the maximum tiller
number stage varied with spacing and fertilizer types, as reflected in
the N absorption pattern of the plants. Yield, sink size and potential
sink size of the plants reflected the N absorption pattern and the amount
of N in the plants. The yield of 6g N-MS10 was almost equivalent to the
yield of 12g N-AS. The yield of MS10 plots was especially higher, with
narrow spacing due to N absorption during the early growth stage.