Effects of different types of fertilizers and methods on dry matter production, yield and nitrogen use efficiency of rice cultivars under field conditions

　To examine the effects of different types of fertilizers and application methods on dry matter production, yield, nitrogen accumulation and use efficiency in rice cultivars, we used two rice cultivars (Nipponbare and Takanari) and five fertilizer methods, i.e. Control (0N), Conventional method, Deep fertilizer method, Standard fertilizer method and High fertilizer method in 2009. Dry matter production was more markedly increased with nitrogen fertilizer application than in control, and it was higher with deep fertilizer application in Takanari and standard fertilizer application in Nipponbare, respectively. The differences in dry matter production resulted from CGR and mean LAI in rice cultivars. Greater dry matter production was accompanied with the nitrogen accumulation at harvesting. Rice cultivars accumulated the largest amount of nitrogen at deep fertilizer application. Higher fertilizer application increased the number of panicle and total spikelets m–2. The higher grain yield in Takanari resulted from the larger sink capacity. The grain yield of rice cultivars tended to be higher with deep fertilizer application due to the increase in sink capacity. Both deep fertilizer application and basal application of slow-release fertilizer increased the recovery efficiency and partial factor productivity of applied N, however, using slow-release fertilizer is recommended in terms of labor saving and lower cost.

原著論文 (Original paper)