Nitrogen management for infant rice seedlings with extended nursery duration by delayed transplanting.

摘要

This experiment was carried out to elucidate the appropriate split application method of nitrogen fertilizer in infant rice seedlings which show poor seedling growth resulted from extended seedling nursery duration more than 12 days. The 16 day-old infant rice seedling (DOIRS) showed poor seedling growth than 8 day-old seedling. Early growth of transplanted 16 DOIRS was poor, compared with that of transplanted 8 DOIRS. However, the poor plant growth estimated by plant height, tiller number, and the number of newly developed roots was compensated by 70-0-30% (basal-tillering-panicle initiation) of nitrogen split application. In 70-0-30% plots among split nitrogen application methods, tiller number, biomass, and leaf area at heading stage of rice showed the highest values. Sixteen DOIRS plots showed lower grain filling and 1000-grain weight, resulted in lower yield of rice than 8 DOIRS plots in the same nitrogen split application. However the lower yield in 16 DOIRS plots was recovered by 70-0-30% of nitrogen split application method to a similar level in 8 DOIRS plots in which nitrogen was split applied by 40-30-30%.