Objective Effects of one-time application of controlled-release bulk blending fertilizer (CRBF) on the grain yield and nitrogen utilization efficiency of double-cropping rice farming in tropical regions were studied.
Method Field experiments were carried out in Fengmu Town, Tunchang County and Dongcheng Town, Danzhou City in Hainan Province during 2016 rice growing season. The conventional fertilization applied in 3 separate times (T1) was implemented along with one-time applications of CRBF without N reduction (T2), with 10% N reduction (T3), and with 20% N reduction (T4). Grain yield, N uptake, and N utilization efficiency on the double-cropping rice cultivation were determined at harvest.
Result The one-time applications of CRBF promoted N absorption and dry matter accumulation with improved grain yield and N utilization of the rice plants. In comparison to T1, they increased 7.43%–22.84% on the grain yield, 8.22%–22.39% on the above-ground dry matter accumulation, 12.19%–32.06% on the N accumulation, and 31.67%–75.65% on the N recovery efficiency based on an equal N input of CRBF. Except for the yield of early rice at Dongcheng site, the differences were significant. Moreover, T2 also surpassed T3 and T4 mostly on grain yield, dry matter, and N content as well as N recovery efficiency.
Conclusion By applying CRBF once annually for the base fertilization, the grain production and N fertilizer utilization of rice plants were significantly improved over the conventional practice. Furthermore, a 10%–20% reduction on N fertilizer did not significantly lower the grain yield. Thus, the application not only simplified the operation but also benefitted the grain production and conserved N for the double cropping rice farming in the tropical regions.
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