氮肥调控剂施用对小麦生长、氮素利用及氮素表观平衡的影响

Effects of Nitrogen Regulator on Wheat Growth,Nitrogen Use Efficiency and Apparent Nitrogen Balance

采用大田试验方法，探讨氮肥调控剂的施用对冬小麦生长、氮素利用及氮素表观平衡的影响。结果表明：双氰胺（DCD）的施用可显著提高小麦秸秆生物量和产量，提高幅度分别达到15．24％～20．37％和8．96％～26．85％；施用DCD后氮肥利用效率有了显著提高，其中氮肥偏生产力、氮表观利用率、氮素吸收效率以及氮素农学效率分别提高8．96％～26．87％，70．39％～81．33％，13．25％～30．34％和53．61％～74．36％；在返青期提高表层土壤硝态氮累积量17．18％～49．42％；在返青期和成熟期，0—100cm土壤剖面硝态氮累积量分别下降12．50％～14．88％和11．69％～12．84％；氮素平衡盈余量降低幅度达23．09％～60．69％。但邢台宁晋试验区，即使DCD与尿素同施，氮素平衡盈余量仍达到53．58～95．08kg／hm2，氮素平衡盈余率在24％以上，仍旧存在较大的环境风险。因此，在考虑小麦季施肥方案时应该适当减少氮肥施用量，并配合施用硝化抑制剂，以保持农田生态系统中氮库的基本平衡。

Field experiments were conducted to study the effects of nitrogen regulator on growth of winter wheat, nitrogen use efficiency and apparent nitrogen balance. The results indicated that, applying dicyandiamide （DCD） could significantly increase the biomass of wheat straw and yield by 15.24%--20.37% and 8.96%- 26. 85%, respectively. Moreover, it could improve the partial factor productivity, apparent utilization efficiency, absorption efficiency and agronomical efficiency of nitrogen by 8. 96%-26. 87%, 70. 39% 81.33%, 13.25%--30. 34% and 53. 61%-74. 36%, respectively. The inhibiting effect of DCD on soil nitrification enhanced the nitrate accumulation in surface soil by 17.18%--49.42% at returning green stage, but decreased the total nitrate accumulation in 0--100 cm soil profile by 12.50%-14.88% and 11.69%- 12. 84% at returning green stage and maturing stage, respectively. And the nitrogen surplus amount reduced by 23.09%--60. 69%. While the nitrogen surplus amount reached 53. 58%95. 08 kg/hm2, and nitrogen surplus rate kept more than 24% in the treatments with DCD in Ningjin county of Xingtai city, which meant the more seriously environmental risk. Considering the fertilization scheme of wheat, the optimum amount of nitrogen with DCD should be recommended so as to keep the apparent nitrogen balance in farmland ecosystem.