控失尿素与普通尿素配施对水稻产量及氮肥利用效率的影响

为探讨控失尿素与普通尿素配施在海南省水稻上的应用效果，通过 2016 年和 2017 年两季田间试验，采用随 机区组设计，以不施氮肥处理作为对照（CK），设置常规尿素（CU）与控失尿素（CLU）不同配施比例，在等氮量条 件下，设 100% CU、70% CU+30% CLU、50% CU+50% CLU、30% CU+70% CLU 和 100% CLU 5 个处理，分析水稻叶 绿素含量、稻谷产量及其构成因子、氮吸收累积量、氮肥利用效率以及经济效益等指标。结果显示，施氮显著增加稻 谷产量，与 CK 相比，增幅为 67.2%~82.0%（2016 年）和 36.7%~46.7%（2017 年）。30% CU+70% CLU 的稻谷产量和 有效穗均显著高于 100% CU 处理，产量增幅为 8.8%（2016 年）和 7.3%（2017 年），有效穗数增幅为 14.2%（2016 年） 和 12.0%（2017 年）。随着 CLU 所占比例的提高，水稻地上部氮吸收累积量、氮肥回收利用率和农学利用率均呈增加 趋势。与 100% CU 处理相比，其余控失尿素处理的氮肥回收利用率增幅为 12.3%~18.4%（2016 年）和 12.7%~17.7%（2017 年），氮肥农学利用率增幅为 20.8%~21.9%（2016 年）和 16.8%~23.5%（2017 年）。随着 CLU 所占比例的提高，水稻 总产值和相对净收益呈先增加后降低的趋势，30% CU+70% CLU 处理达到最大。综上所述，在本试验条件下，30% CU+70% CLU 能够获得较高的稻谷产量、氮肥利用效率及经济效益，其可作为该地区氮肥施用的推荐比例。

Effects of Combined Application of Common Urea and Controlledloss Urea on Grain Yield and Nitrogen Use Efficiency in Paddy Rice

Field trails were conducted to study the application effects of CLU (controlled-loss urea) and CU (common urea) for rice with randomized block design in 2016 and 2017 in Hainan. The treatments included no nitrogen fertilization as the control (CK) and 5 fertilizations under the same N rates, i.e., 100% CU, 70% CU+30% CLU, 50% CU+50% CLU, 30% CU+70% CLU and 100% CLU, respectively. The chlorophyll of leaves, grain yields and its components, N uptake, N use efficiency and economic profit were analyzed. The results showed that grain yield significantly increased by 67.2%–82.0% in 2016 and 36.7%–46.7% in 2017 under the condition of N fertilization compared to CK. Among all N fertilization treatments, grain yield and effective panicles of 30% CU+70% CLU were the highest. Compared with the 100% CU, grain yield was increased by 8.8% in 2016 and 7.3% in 2017, and the effective panicles were increased by 14.2% in 2016 and 12.0% in 2017 for the treatment of 30% CU+70%CLU, respectively. The N uptakes of whole plants, N recovery efficiency (NRE) and N agronomy efficiency (NAE) gradually increased as the ratios of CLU in total urea-N increased. Compared with the 100% CU, the NRE increased by 12.3%–18.4% in 2016 and 12.7%–17.7% in 2017, while the NAE increased by 20.8%–21.9% in 2016 and 16.8%–23.5% in 2017 for the other treatments of CLU. The economic profit increased firstly to the higher value for the treatment of 30% CU+70% CLU, while decreased secondly as the ratios of CLU in total urea-N increased. To summarize, 30% CU+70% CLU fertilization could be used as the feasible ratio to get desirable grain yields, N use efficiency and economic profit under this experimental conditions.