氮肥管理措施对黑土春玉米产量及氮素利用的影响

利用连续2年田间试验,研究不同氮肥管理措施对黑土春玉米产量及氮素利用的影响。结果表明,在农民习惯施氮量185 kg/hm2的水平上,减施氮肥20%不影响玉米子粒产量和氮素吸收,氮肥表观利用率和氮肥偏生产力提高22.4%~29.2%和18.4%~22.3%。与习惯施肥处理相比,减施氮肥可显著降低土壤硝态氮含量,0~20、21~40、41~60和61~80 cm土层硝态氮含量降幅分别为14.3%~53.8%、13.0%~32.6%、17.9%~36.8%和13.7%~41.2%。同一施氮量下,添加硝化抑制剂有助于抑制土壤硝化作用,添加双氰胺0~20、21~40 cm土层硝态氮含量分别下降45.7%和28.5%,添加2-氯-6-三氯甲基吡啶分别下降39.7%和21.8%。综合评价玉米产量、氮素吸收和氮肥利用等因素,应适当减少施氮量,并配合施用硝化抑制剂2-氯-6-三氯甲基吡啶,促进农田生态系统中氮素高效利用和维持氮库基本平衡。

Effects of Nitrogen Fertilizer Management on Spring Maize Yield and Nitrogen Utilization in Black Soil

Two year field experiments were conducted to determine the effects of different nitrogen fertilizer management on spring maize yield and nitrogen utilization in black soil. The results showed that, compared with the conventional fertilization with higher rates of N fertilizer(185 kg N/ha), the grain yield and N uptake of maize had no significant change under the management of decreasing the N amendments to 20%, whereas N apparent utilization efficiency and N partial fertilizer productivity were increased by 22.4%-29.2% and 18.4%-22.3%, respectively. Compared with the treatment of conventional fertilization, the management of reduction of N amendment significantly decreased NO₃^--N contents in soil layers of 0-20, 21-40, 41-60 and 61-80 cm by 14.3%-53.8%, 13.0%-32.6%, 17.9%-36.8% and 13.7%-41.2%, respectively. Compared with the treatment of urea alone, NO₃^--N contents in soil layers of 0-20 and 21-40 were decreased by 45.7% and 28.5% by applying dicyandiamide(DCD), while 39.7% and 21.8% by applying nitrapyrin under the same N application rate. Based on yield, N uptake and N apparent utilization efficiency, considering the fertilization scheme of wheat, the optimum amount of decreasing N rate by 20% with nitrapyrin should be recommended so as to promote high use efficiency and keep the apparent nitrogen balance.