Effect of Slow Release Fertilizer (Meister) on the Nitrogen Uptake and Yield of the Rice Plant in the Tropics

Abstract

Field experiments on the response of rice plants to slow release fertilizer (Meister 10, MS10) were conducted from the 1986 wet season (WS) to the 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 spacings. In all experimental plots regardless of season, the amount of N in the plants increased exponentially at the early growth stage (y = ab^x) and linearly at the middle and late growth stages (y = a + bx), as previously reported. MS10 lengthened 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.