Yield and N Utilization of Transplanted and Direct-Seeded Rice with Controlled or Slow-Release Fertilizer

To understand the response of rice yield and N utilization to controlled or slow-release fertilizers (CSRFs) under direct-seeded or seedling-transplanted modes of rice production, a field experiment with rice variety Wuyunjing 23 was performed in 2013 and 2014. Five treatments, including two CSRFs: sulfur-coated urea (SCU) and resin-blending controlled-release fertilizer (RBB), two fertilization modes: single basal application and a split "base-panicle" (BP) application, and conventional split fertilization (CONV) as a control, were conducted. The results showed that there was no improvement of yield for SCU application compared with CONV in the seedling-transplanted and direct-seeded modes in both years. The yield increasing effect of RBB was better than that of SCU under the two planting modes. The interaction effect between the planting mode and fertilizer treatment on the yield was significant. The yield of RBBBP treatment was the highest in seedling-transplanted fields, reaching 12.04 t ha(-1) in 2013 and 13.44 t ha(-1) in 2014. By contrast, the yield of RBBbasal treatment was the highest in direct-seeded rice, although the difference among the treatments was not significant. The CSRF application (RBBbasal, RBBBP, SCUBP) increased the NUE in both the seedling-transplanted and direct-seeded fields. Except for the NUE of RBBbasal, which was the highest for direct-seeded rice in 2013, the RBBBP treatment showed the highest NUE in seedling-transplanted and direct-seeded rice in both years. The results indicated that RBB increased the yield and NUE in both seedling-transplanted and direct-seeded modes, and the combined panicle urea and RBB was better in seedling-transplanted fields, while a single basal application with RBB was better in direct-seeded rice.