控释尿素对土壤供氮能力及旱作玉米产量的影响

通过田间试验,探明控释尿素输入对土壤无机氮变化及春玉米氮素吸收利用特性的影响,为宁夏南部山区氮肥高效利用及玉米高产提供理论依据和技术支撑。以"先玉698"为供试材料,在等氮量(225 kg/hm~2)条件下,以不施氮为对照(CK),设置UR(100%普通尿素,2/3基施,1/3小喇叭口期追施)、CRU1(1/3控释尿素+1/3普通尿素基施,1/3普通尿素小喇叭口期追施)、CRU2(2/3控释尿素+1/3普通尿素一次基施)、CRU3(100%控释尿素基施)4种施氮模式,探明控释尿素输入对土壤无机氮分布、玉米氮素吸收运转、氮素利用效率以及产量的影响。结果表明,相对于UR处理,控释尿素输入显著提升了春玉米生育中后期土壤硝态氮和铵态氮的含量,其中以CRU2处理效果最明显。CRU输入能提高春玉米产量及氮肥利用率,与UR相比,2年内平均增产0.67 t/hm~2,氮肥偏生产力提高2.92 kg/kg,氮肥利用率提高6.02%。CRU处理间尤其以CRU2效果最佳,与CRU1、CRU3相比,2年内分别平均增产0.10,0.53 t/hm~2,氮肥偏生产力分别提高0.30,2.23 kg/kg,氮肥利用率分别提高2.49%,9.44%。由此可见,控释/普通尿素配施有利于提高土壤养分供应与春玉米氮素吸收的吻合度,初步建议采用控释尿素基施150 kg/hm~2+普通尿素基施75 kg/hm~2的施肥模式,以提高宁夏旱区春玉米产量和氮肥利用率。

Effects of the Controlled Release Urea Application on Soil Nitrogen Supply in the Mid-late Growing Stage and Yield in Rainfed Maize

Based on field experiment,the influence of controlled release urea (CRU) application on soil inorganic nitrogen distribution,nitrogen uptake and use characteristics of spring maize (Zea mays L.) was analyzed to provide theoretical basis and technical support for high-efficiency utilization of nitrogen fertilizer and high-yield maize in the southern mountain area of Ningxia. Xianyu 698 was used as experimental material. Five treatments that including No nitrogen was applied as the control (CK),conventional nitrogen supply UR (100% Urea (U),1/3 U base application,1/3 U flare opening period application),CRU1 (1/3 CRU + 1/3 U base application,1/3 U flare opening period application),CRU2 (2/3 CRU + 1/3 U base application),and CRU3 (100% CRU base application) were designed to explore the effects of CRU input on soil inorganic nitrogen distribution,nitrogen uptake,nitrogen use efficiency and yield of maize. The results showed that the soil nitrate nitrogen and ammonia nitrogen content in the mid-late stage of maize with the CRU treatments was significantly increased compared with those of UR treatment,with the highest increase in CRU2 treatment. CRU input could improve the yield and nitrogen utilization of spring maize. Compared with UR,the average yield of spring maize increased by 0.67 t/hm²,the nitrogen partial factor productivity (NPFP) increased by 2.92 kg/kg,and the nitrogen use efficiency (NUE) increased by 6.02%. Compared with CRU1 and CRU3 treatments,the yield,NPFP,and NUE in CRU2 treatment within two years were significantly increased by 0.10 t/hm² and 0.53 t/hm²,0.30 kg/kg and 2.23 kg/kg,2.49% and 9.44%,respectively,indicating that the positive responses of yield,NPFP,and NUE to CRU2 in all CRU treatments. Comprehensively,under reasonable distribution conditions,the blending of UR and CRU had a significant effect on increasing the soil nutrient supply and nitrogen absorption in spring maize. Therefore,we suggested that 2/3 CRU+1/3 U base application for rain-fed maize in Southern Ningxia.