Mineralization of soil organic nitrogen and nitrogen absorption by rice [Oryza sativa] plant as affected by drying duration
1995
Ando, H. (Yamagata univ., Tsuruoka (Japan). Faculty of Agriculture) | Marumoto, T. | Wada, G. | Nakamura, T.
The effects of moisture content of soil and drying duration on the mineralization of soil organic N and N absorption by rice plants were evaluated using paddy soils derived from alluvial sediment and volcanic soils in tropical and temperature areas. The results obtained are as follows: 1) The amount of N mineralized for 4 weeks incubation increased with the decreasing soil-to-water ratio. No significant difference was observed in the water content of soil when the drying duration was more than 4 d. However, the longer the duration of drying, the greater the amount of N was mineralized irrespective of the soils' parent materials and the areas where it was obtained. 2) There were significant differences in the dry weight and amount of N in rice plants among treatments. The amount of N in rice plants increased with the increasing duration of drying up to 6 weeks. However, the dry matter increase of the rice plant grown in soil dried for 8 weeks was smaller than the other treatments despite the highest N mineralization observed in this soil. 3) the mineralization rate of soil organic N was higher at 1 or 2 weeks after incubation than at 3 or 4 weeks
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