Evaluation of Nitrogen Fertilizer and Cultivation Methods for Agronomic Performance of Rice

Nitrogen fertilization and cultivation methods are the two principal management approaches used in agronomy to determine the growth and grain yield of rice. In this study, a field experiment was conducted to evaluate the performance of three cultivation methods (conventional manual transplanting of field-grown seedlings [TFS], direct seeding [DS], and transplantation of glasshouse-grown seedlings followed by manual transplanting [TGS]) under two N management treatments (split applications of urea [PU] vs. a single basal application of a controlled-release fertilizer [CRF]) for growing rice under a subtropical monsoon climate in China (2011-2014). Annual grain yield, yield components, and total biomass were determined at maturity over the 4-yr experiment. We also measured the dry matter, leaf area index, leaf area duration, and leaf chlorophyll "greenness" of rice at key growth stages. Over the 4 yr, the comparative grain yield of CRF significantly exceeded that of PU with TFS and TGS by 7.7 and 5.2%, respectively, suggesting that CRF was best for transplanted rice. In the case of DS, however, CRF reduced grain yield by 3% compared with PU. The grain yields of TFS and TGS were significantly higher than that of DS rice (by 8.2 and 11.6%, respectively) under the PU treatment and were higher under the CRF treatment (by 20 and 21%, respectively). Our results suggest that these two transplanting methods, when coupled to controlled-release fertilizer management, could be an effective way to achieve higher rice grain yields.