**4.1 Smart nitrogen fertilizer management**

Management of no other fertilizer nutrient presents a great challenge to the rice. The N fertilizer rate required to achieve optimum yield in rice can be influenced significantly by the preceding crop. The nitrogen fertilizer rate required to produce the best grain and milling yield of rice is dependent on rice genotypes, stand density, previous crops, straw management, soil texture, permeability, N fertilizer methods, water management, soil reaction, tillage and N fertilizer source. In rice plant nitrogen fertilizer loss mainly by nitrification and denitrification, and diffusion (**Figure 3**) [8, 9].

Rice grain yield mainly affected by the number of tillers, which, in turn, is influenced by the N fertilizer rates. The application of N for rice highly depends on soil separates content. In sandy soil with low CEC fertilizer is subjected to considerable leaching losses, higher N rate or multiple N applications may be considered to overcome losses. The clay soils generally need 40–60 kg N/ha more N fertilizer than those rice grown on silt loams to achieve similar grain yield. The use of climate smart nitrogen fertilizer like: neem coated, sulfur coated, polyamine coated that may improve yield of rice under tough soil and climate condition [12].
