Accumulation and utilization of nitrogen, phosphorus and potassium of irrigated rice cultivars with high productivities and high N use efficiencies

•This study focused on combined increase of rice yield and nitrogen (N) use efficiency in rice.•The larger N, phosphorus (P) and potassium (K) accumulation increased rice yield.•The increased N, P, K accumulation from heading to maturity combined the high yield and high N use efficiency in rice.•The N, P and K accumulation in grains at maturity did not explain high N use efficiency of high yield cultivars.

In the Jiangsu province of Southeast China, high irrigated rice yields are supported by high nitrogen (N) fertilizer inputs and low fertilizer N use efficiencies. A little attention has already been paid to the combined increase of rice yield and N use efficiency, however, the accumulation and utilization of N, phosphorus (P) and potassium (K) of irrigated rice genotypes with high yield and N use efficiency is still obscure. Field experiments were conducted in 2010 and 2011 where two cultivars with low productivity and low N use efficiency (LPLNE), two cultivars with high productivity and medium N use efficiency (HPMNE) and two cultivars with high productivity and high N use efficiency (HPHNE) were grown separately under their respective optimum N application to achieve maximum attainable yields. Accumulation and utilization of N, P and K as well as their interacting relationships were studied. The results showed that: (i) When values were averaged across cultivars and years, compared with LPLNE, HPMNE and HPHME showed 18.1, 25.3, and 9.6% higher N, P, K accumulations at maturity, respectively. The N grain production efficiency (NGPE) and K grain production efficiency (KGPE) were both higher, although P grain production efficiency (PGPE) showed no consistent tendencies; (ii) When values were averaged across cultivars and years, in comparison with HPMNE, HPHNE achieved a 1.7% lower total N accumulation, but a 6.5% higher N accumulation during the period from heading to maturity. At maturity, N accumulation in leaves increased by 3.5% and that in grains decreased by 4.0%. Total P and total K accumulation increased by 2.5% and 2.8%, respectively, which was mainly attributed to greater accumulation after panicle initiation, especially in the period from heading to maturity. At maturity, P accumulation in leaves increased by 11.5% and that in stems and grains did not differ significantly, K accumulation in stems increased by 4.2% and that in leaves and grains did not differ significantly. The N, P and K accumulation in grains at maturity did not explain the higher N use efficiency of HPHNE. This study suggested that a decrease of N accumulation before panicle initiation and increase of N, P, K accumulation during the period from heading to maturity may be helpful to combine the high yield and high N use efficiency in rice.