Effects of nitrogen fertilizer rates on dry matter accumulation and transportation in ratoon rice

Effects of nitrogen fertilizer rates on dry matter accumulation and transportation in ratoon rice were studied. The results showed that the photo-production was significantly enhanced in main rice exposed to optimum nitrogen application rate used to promote bud and tiller, dry matter accumulation in leaves and stem-sheath increased, the stubble of main rice remained the larger share in the dry matter after harvesting, contributed to the increase of productive tillers and leaf areas, so photosynthetic products of ratoon rice increased. It was also found that the optimum nitrogen application had very important role in increasing transported rate of dry matter from the stubble and leaves of main rice, leading to significantly increase of the dry matter accumulation in ratoon rice. In the period from full heading to ripening of ratoon crop, the net accumulation of dry matter, panicle number and grain yield were parabolically related to the nitrogen application rate used to promote bud and tiller. The grain yield of ratoon crop exposed to 241. 3 kg·hm-2 was the highest.