控释尿素与常规尿素配施比例对甜玉米产量和氮肥利用的影响

摘要

[目的]研究在不同施氮水平下,控释尿素与普通尿素不同组配比例施用对甜玉米生长、产量及氮肥利用率的影响,为控释尿素在甜玉米生产上的推广应用提供参考. [方法]2015年在广东省博罗县和惠阳县以当地主栽品种华珍和粤甜9号开展田间试验.试验共设7个处理:不施氮(CK);施尿素N 360kg/hm2 (U1);减施尿素30％ (252 kg/hm2,U2);40％控释尿素,减氮30％ (252 kg/hm2,40％ CRU1);40％控释尿素,减氮50％(180 kg/hm2,40％ CRU2);60％控释尿素,减氮30％ (252 kg/hm2,60％ CRU1);60％控释尿素,减氮50％(N 180 kg/hm2,60％ CRU2).乳熟期采集甜玉米植株样品进行养分分析,每小区单独采收后记录产量和产量构成要素. [结果]施氮显著提高甜玉米鲜苞产量(P＜0.05).且随着施氮量的增加,甜玉米鲜苞产量逐渐提高.U1处理的鲜苞产量最高,其次是60％ CRU1处理,40％ CRU2处理的鲜苞产量显著降低.60％ CRU1处理的甜玉米鲜苞产量与U1基本持平.在等氮条件下,甜玉米鲜苞产量表现为60％CRU＞ 40％ CRU＞U,两地结果一致.施氮主要提高甜玉米穗长、穗粗和行粒数,显著提高甜玉米物质累积量和氮素吸收累积量(P＜0.05),秸秆和籽粒的平均增幅分别为55.1％和24.2％,95.0％和43.4％,秸秆增幅更大.甜玉米物质累积量和氮素吸收累积量随着施氮量的增加而提高;在等氮条件下,甜玉米物质累积量和氮素吸收累积量均表现为60％CRU＞40％ CRU＞U,以60％CRU处理的氮肥农学效率、氮肥偏生产力和氮肥吸收利用率最高,其次是40％CRU处理,U处理最低.不同施肥处理对氮肥生理利用率和氮收获指数没有影响.不同施肥处理对甜玉米维生素C和可溶糖含量没有影响. [结论]控释尿素与普通尿素配施处理的甜玉米产量、物质累积量和氮素吸收累积量均优于常规施肥处理,且随着控释尿素配施比例的增加而增加.在甜玉米生产中,控释尿素与普通尿素配施可显著提高氮肥利用效率,是甜玉米化肥减施增效的有效途径.%[Objectives] Effects of different blending rates of controlled-release urea (CRU) and conventional urea (U) at different N amounts on growth,grain yield,nitrogen uptake and nitrogen efficiency of sweet corn were studied to provide reference for the application and dissemination of CRU in sweet corn production.[Methods] Field experiments of sweet corn were carried out using sweet corn cultivars of Huazhen and Yuetian 9 as tested materials in Boluo County and Huiyang County of Guangdong Province simultaneously in 2015.Conventional urea and controlled-release urea were mixed in different ratio and total N input in different rate.No nitrogen fertilizer as CK,urea N 360 kg/hm2 (U1),252 kg/hm2 (U2),N 252 kg/hm2 with 40％ CRU (40％ CRU1),N 180 kg/hm2 with 40％ CRU (40％ CRU2),N 252 kg/hm2 with 60％ CRU (60％ CRU1),and N 180 kg/hm2 with 60％ CRU (60％ CRU2).All treatments were fertilized with P2O5 157 kg/hm2 and K2O 360 kg/hm2.Straw and ear of sweet corn were collected at maturity period for the N analysis.The yield and yield components were also recorded after the harvest.[Results] The ear yields of sweet corn were increased significantly due to the nitrogen applications (P ＜ 0.05),and increased as more nitrogen was applied.The highest ear yield of sweet corn was achieved under the U 1,and the second highest yield was obtained under the 60％ CRU 1,but that of the 40％ CRU2 decreased significantly.No significant differences between the U1 and the 60％ CRU1 were observed.On the basis of the uniform N rate,the yields of different treatments at the two sites were all in order:60％ CRU ＞ 40％ CRU ＞ U.The application of N fertilizers mainly increased the ear yield through increasing the ear length and diameter and kernel number per row.The accumulative amounts of dry matter and N uptake of sweet corn were increased significantly by applying N fertilizers,the average increases of dry matter and N uptake in straw and kernel were 55.1％ and 24.2％,and 95.0％ and 43.4％,and the increases in the straw were greater.The accumulative amounts of dry matter and N uptake of sweet corn were increased due to more N applied.And on the basis of the same N rate,accumulative amounts of dry matter and N uptake of sweet corn under different treatments at the two sites were in order:60％ CRU ＞ 40％ CRU ＞ U.On the basis of the same N rate,the agronomic N use efficiencies,partial factor productivities of N fertilizer and N recovery efficiencies of different treatments at the two sites were all in order:60％ CRU ＞ 40％ CRU ＞ U.But no significant differences in the physiology efficiencies of nitrogen and nitrogen harvest indices among different treatments were observed.There were no significant differences in Vc and soluble sugar contents of sweet corn among different treatments.[Conclusions] The yield,dry matter and N uptake of sweet com were increased due to the blending application of controlled-release urea and urea,and increased more with controlled-release urea addition of 60％.The blending application of controlled-release urea and urea could benefit to the nitrogen utilization efficiency of sweet corn,and be potential way to decrease the total N fertilizer input.