Effects of top-dressed nitrogen and rhizosphere sizes on nitrogen uptake and translocation at maturity in paddy rice [Oryza sativa]
1992
Akita, K. (Kobe Univ. (Japan). Faculty of Agriculture) | Tanaka, N.
This study was carried out to clarify the effects of rhizosphere sizes and top-dressing time on nitrogen absorption and translocation at maturity in paddy rice (Oryza sativa L. cv. Nipponbare). Rhizosphere was restricted by three different sized pots (1/5030a, 1/2020a and 1/1050a). 15N-labelled ammonium sulfate was top-dressed at seven different times (five day intervals) between 20 days before and 10 days after heading. In all plots, the total dry weight and nitrogen content increased with increasing rhizosphere size without any conceivable effects of top-dressing time. The 15N uptake also increased with increasing rhizosphere size and the highest uptake was obtained when applied 10 days after heading. In terms of nitrogen distribution, when top-dressed 20 days before heading, most of the 15N was accumulated in the leaf blade, whereas later top-dressed nitrogen tended to accumulate in the ear
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