Controlled-release fertilizer enhances rice grain yield and N recovery efficiency in continuous non-flooding plastic film mulching cultivation system

摘要

Non-flooding plastic film mulching (PM) cultivation is a promising water-saving technology for rice cultivation. However, because the N fertilizer can only be applied before transplanting due to technical difficulties with later applications, it results in excessive vegetative growth and potential N shortages during the reproductive stages, which may limit grain yield potential. The use of polymer-coated urea (PCU), a slow release N fertilizer, has become one of the best management practices for increasing crop yield and improving N recovery efficiency in traditional flooded rice cultivation (TF), but has not been tested in PM cultivation. The objective of the eight-year (2008-2015) field experiment in the present study was to compare the effects of PCU with a conventional prilled urea fertilizer (PU) and a control (no N fertilizer applied; CK) on grain yield, N recovery efficiency, yield components, and soil nutrients under PM and TF cultivation systems. Within fertilizer treatment, plant N uptake and N recovery efficiency were almost always significantly higher in the PM than the TF cultivation treatments. PCU application significantly increased these parameters in both cultivation systems, but usually by significantly more with PM cultivation. Compared to the PU treatment, PCU significantly increased rice grain yield in both cultivation systems every year (by means of 11% and 15% in the TF and PM, respectively), except for TF in the first year. Within fertilizer treatment, yields of PM and TF were similar. In comparison with PU, the use of PCU had no effect on soil organic matter or alkali-hydrolyzable N. However, PM cultivation decreased these parameters. In conclusion, PCU application increased the N recovery efficiency and N availability in both cultivation systems during the reproductive stages of rice, and thus improved rice grain yield. We demonstrated that the application of PCU is a practical N fertilizer management technique that improves rice grain yield and N recovery efficiency, and is an effective solution to fertilization challenges in PM rice cultivation systems.