NPK Accumulation and Use Efficiencies of Manawthukha Rice (Oryza sativa L.) Affected By Pretransplant Basal and Split Applications of Nitrogen

We investigated the effects of split applications of nitrogen (N) on N, phosphorus, and potassium (NPK) uptake and use efficiency of rice under basal surface-application and incorporation methods. Different amounts of N were applied at the basal, tillering, and panicle initiation stages in five N split treatments. Basal incorporation provided greater NPK uptake than basal surface application until initiation of the panicle. In basal surface application, N2 (25:50:25) resulted in the greatest total NPK uptake, use efficiency, and N recovery efficiency. In basal incorporation, N1 (50:25:25) resulted in greater values for all parameters. The N5 (50:0:50), which included omitting N at tillering, resulted in low N recovery efficiency and uptake, both under basal incorporation and basal surface application. These results emphasize that split applications of N influence N recovery efficiency and total NPK uptake and use efficiency of rice.