Pengaruh Dosis Nitrogen terhadap Pembentukan Tunas dan Pertumbuhan Padi Ratun (Oryza sativa L.)

Food security is the government's top priority in eradicating hunger. The government continues to make an innovation, so that food needs in Indonesia are fulfilled. One of them is increasing the rice harvest index to 5 times through the ratoon system. Currently, ratoon productivity is only 40-50% lower than its parent plant. Utilization of technology in the ratoon system is expected to increase plant productivity. This study aims to increase the productivity of the ratun by increasing the number of tillers which increase the growth of the ratoon. The experiment was arranged in completely randomized design (CRD). The factor tested were nitrogen dose (50 kg ZA / ha, 100 kg ZA / ha, 150 kg ZA / ha, 200 kg ZA / ha, and 250 kg ZA / ha) repeated 4 times. The parent rice plant which used in the ratoon system was Inpari-32 variety. Collecting data were consisted number of tillers, length of panicles, number of grains per panicle, number of pithy grains, number of empty grains, and leaf chlorophyll content. The result showed that nitrogen application 100, 150, 200, and 250 kg ZA.ha-1 has a significant effect on number of tillers compared to 50 kg ZA.ha-1, but it was not significant for the other observed variables. The optimum nitrogen dose to achieve the maximum number of tillers was 216.75 ZA.ha-1. Increasing the level of nitrogen disposed to increase plant growth and yield component of ratoon rice, although it was not significant difference.