• ISSN 1008-505X
  • CN 11-3996/S
刘艳妮, 马臣, 于昕阳, 梁路, 翟丙年, 王朝辉. 基于不同降水年型渭北旱塬小麦–土壤系统氮素表观平衡的氮肥用量研究[J]. 植物营养与肥料学报, 2018, 24(3): 569-578. DOI: 10.11674/zwyf.17374
引用本文: 刘艳妮, 马臣, 于昕阳, 梁路, 翟丙年, 王朝辉. 基于不同降水年型渭北旱塬小麦–土壤系统氮素表观平衡的氮肥用量研究[J]. 植物营养与肥料学报, 2018, 24(3): 569-578. DOI: 10.11674/zwyf.17374
LIU Yan-ni, MA Chen, YU Xin-yang, LIANG Lu, ZHAI Bing-nian, WANG Zhao-hui. Nitrogen application rate for keeping nitrogen balance in wheat–soil system in Weibei rainfed areas under different rainfall years[J]. Journal of Plant Nutrition and Fertilizers, 2018, 24(3): 569-578. DOI: 10.11674/zwyf.17374
Citation: LIU Yan-ni, MA Chen, YU Xin-yang, LIANG Lu, ZHAI Bing-nian, WANG Zhao-hui. Nitrogen application rate for keeping nitrogen balance in wheat–soil system in Weibei rainfed areas under different rainfall years[J]. Journal of Plant Nutrition and Fertilizers, 2018, 24(3): 569-578. DOI: 10.11674/zwyf.17374

基于不同降水年型渭北旱塬小麦–土壤系统氮素表观平衡的氮肥用量研究

Nitrogen application rate for keeping nitrogen balance in wheat–soil system in Weibei rainfed areas under different rainfall years

  • 摘要:
    目的 研究渭北旱区不同降水年型氮肥用量对小麦–土壤系统氮素表观平衡的影响规律,以实现作物稳产、平衡土壤氮素携出、避免过多氮肥残留累积为目标,通过3年田间定位试验,探讨渭北旱区冬小麦稳产增效的最佳氮素投入量。
    方法 2011年7月—2012年6月降水量为710.1 mm,高于年均降水量 23.1%,属于丰水年;2012年7月—2013年6月降水量为391.4 mm,低于年均降水量 32.2%,属于欠水年;2013年7月—2014年6月降水量为603.8 mm,高于年均降水量 4.6%,属于平水年。本研究设置5个氮肥水平 N 0、75、150、225、300 kg/hm2,分别以N0、N75、N150、N225、N300表示,研究不同施氮量对冬小麦产量、吸氮量、氮素表观平衡及收获后土壤硝态氮残留量的影响。通过保证土壤氮素的输入和携出平衡确定氮肥用量,并通过该施氮量下吸氮量、产量及收获后100 cm土层硝态氮累积量加以验证。
    结果 连续3年的定位试验结果表明,产量随降水量的增加而提高。相同降水量条件下,产量随施氮量增加呈先增加后降低的趋势,3年小麦产量均在N225水平达到最大值,但N225与N150水平之间差异不显著,小麦地上部吸氮量与籽粒产量有相似的规律;小麦收获后0—100 cm土层硝态氮残留量也随施氮量的增加而升高。其中50.8%~75.5%的集中在0—40 cm,并且随着年限的延长逐渐减少,3年平均值分别为63.8%、66.1%和53.6%,而40—100 cm土层硝态氮残留量逐年升高且有向下淋溶的趋势;3种降水年型,土壤氮素盈余量 (土壤氮素输入 – 输出) 为0 kg/hm2的氮素盈余指标下的氮素投入量有所不同:丰水年、欠水年和平水年施氮量分别为127、54和103 kg/hm2;在考虑到维持作物产量和土壤肥力而允许氮素表观盈余指标为N 40 kg/hm2时,丰水年、欠水年和平水年施氮量分别为170、99和150 kg/hm2。此时的作物吸氮量 (130、59、110 kg/hm2) 和产量 (6267、2309、4502 kg/hm2) 均能保持在较高水平,与理论最高吸氮量和最高产量值接近,而施氮量与理论最高吸氮量和产量时的施氮量相比有不同程度降低,分别减少了4.7%、142%、21.3%和5.3%、120%、30.7%。小麦收获后100 cm土层硝态氮累积量分别为101.4、104.2和113.7 kg/hm2,不仅可以保持土壤氮库的稳定,还能将残留硝态氮基本维持在安全阈值内 (N 90~100 kg/hm2)。
    结论 综合考虑不同降水年型氮肥用量下冬小麦–土壤系统氮素表观平衡的变化,建议在渭北旱区丰水年、欠水年和平水年施氮量分别为170、99和150 kg/hm2,以保证作物稳产和氮素高效吸收利用。

     

    Abstract:
    Objectives  The apparent nitrogen balance of wheat–soil system in different rainfall years in Weibei dryland were investigated, and the suitable nitrogen rates were proposed for different rainfall years, aiming to keep stable wheat yield, balance the soil nitrogen and avoid excessive nitrogen residue.
    Methods  The rainfall from July 2011 to June 2012 was 710.1 mm, which was 23.1% higher than the average, belonging to humid year; That from July 2012 to June 2013 was 391.4 mm, 32.2% lower than the average, belonging to drought year; From July 2013 to June 2014 was 603.8 mm, 4.6% higher than average and belonging to normal year. A field experiment with five nitrogen application rates of N 0, 75, 150, 225, 300 kg/hm2 (expressed as N0, N75, N159, N225, and N300) had been conducted during the three years. The wheat yield, wheat N uptake, apparent nitrogen balance and the nitrate residue were compared among the three years, and the suitable nitrogen application rate was calculated by the input and output of soil nitrogen, and tested by crop uptake, yield and nitrate accumulation in 100 cm soil layer.
    Results Under the same rainfall, the increase of N application rate led to increment at first and then decrease of wheat yield. Although the highest yields in the three years were all recorded in the N225 treatment, the differences between the N225 and N150 were not significant. The pattern of wheat N uptake was similar with grain yield. The residual NO3-N in 0–100 cm soil layer after wheat harvest was also increased with the increase of N application rate, of which 50.8%–75.5% concentrated in 0–40 cm and gradually decreased with the extension of the years. The residual NO3-N in 40–100 cm soil layer was increased year by year and leached downward deeper. In case of no NO3-N surplus, the nitrogen application rates were N 127, 54 and 103 kg/hm2 respectively in wet, dry and normal years; When the allowable NO3-N surplus was 40 kg/hm2 for stable wheat yield and soil fertility, the nitrogen application rates were N 170, 99 and 150 kg/hm2 respectively in turn, with which the wheat N uptake and wheat yield were close to the theoretical maximum values, and the nitrogen amounts were 4.7%, 142% and 21.3% less than those for maximum N uptakes, and 5.3%, 120% and 30.7% less than those for the maximum yields. The NO3-N surplus in 0–100 cm layer after wheat harvest were 101.4, 104.2 and 113.7 kg/hm2, respectively, which were within the safe threshold of residual nitrate level (N 90–100 kg/hm2).
    Conclusions Considering the differences of nitrogen balance in winter wheat–soil system with different N application rates in different rainfall years, it is suggested that the nitrogen application rates in wet, dry and normal years in Weibei dryland should be N 170, 99 and 150 kg/hm2 respectively to ensure stable crop yield and utilization efficiencies of nitrogen.

     

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