2. Influence of longterm application of ammonium sulfate on growth and yield of rice in present cropping season
1985
Paiboon Prabuddham (Kasetsart Univ., Bangkok (Thailand). Faculty of Agriculture. Dept. of Soil Science)
This was a field trial in the RD7 main plot of the first experiment to investigate present effects of the longterm (30th and 31st cropping seasons) (NH4)2SO4 trials previously studied on growth, yield and chemical compositions of RD23 rice variety in the BWAS and FWAS. Physiological stages selected were tillering stage (4 weeks after transplanting, WAT), primordia initiation stage (6 WAT), flowering stage (10 WAT) and maturing stage (14 WAT). The results of this experiment could be summarized in the following: 1. The influence of longterm (NH4)2SO4 trial brought about: (a) no influence on height and dry matter of root; (b) highly significant and positive increase in tillering and dry matter of the rice top in all physiological stages in both soil groups except at tillering stage in BWAS which was not statistically different; (c) highly significant and positive increase in yield and number of panicles per hill in both soils but only significant. and positive increase in 100 grain weight in only FWAS while for number of grain per panicle no statistical difference was not observed in both soils. 2. Increase N rates still highly significantly increased plant N content but the difference was more pronounced in the earlier stage as well as that of the uptake. 3. Dry matter of top at primordia initiation stage could be a good yield indicator in both BWAS and FWAS but the latter was better.
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