基于文献分析的北方冬麦田氨挥发特性

    Ammonia volatilization from winter wheat cropland in Northern China based on a literature analysis

    • 摘要: 中国北方地区是冬小麦-夏玉米种植体系的主要集约化农业区,过去30多年间化学氮肥投入量大和肥料利用率低的现象较为普遍,氨挥发等农业面源污染严重,需要对冬小麦生长过程中的氨挥发规律及测定方法等进行系统研究。该研究对1980年至2018年的华北平原冬小麦氨挥发文献进行研究总结,采用回归方程和T检验等统计学方法分析了不同施氮水平、施肥时期和测定方法对冬小麦氨挥发的影响。研究发现,随着化肥施氮量的增加,冬小麦氨挥发累积量呈现指数函数增加趋势(y=2.64e0.006 6x),净氨挥发量呈现幂函数增加特征(y=0.004 8x1.358 9)。不考虑激发效应的净氨挥发量比考虑激发效应的高估约21.8%。冬小麦生产中,基追比为1∶1的情况下,基肥期氨挥发量显著高于追肥期氨挥发量(P<0.05),占整个生育期氨挥发量分别为58.7%和41.3%。在180 kg/hm2氮肥水平时,海绵吸收法与真空抽气法测定的氨挥发数量无显著性差异。冬小麦季的氨挥发控制,应该重点通过优化氮肥施用数量,主要在基肥期进行控制。田间生产中,采用海绵吸收法和真空抽气法监测氨挥发应考虑不同施肥水平下的高估。

       

      Abstract: Northern China is the main intensive agricultural area for winter wheat-summer maize production in China. In the past 30 years, chemical nitrogen (N) fertilizer was the main source of N input in the farmland ecosystem and plays a key role in crop production and soil quality. Due to the excessive application of chemical N fertilizer and frequent irrigation, fertilizer N usage efficiency was low and was also lost into the environment and this caused many negative environmental pollutions. Among the fates of fertilizer N applied, ammonia volatilization was an important gaseous N loss, and it was one of the main sources of atmospheric ammonia and significantly contributed to the formation of atmospheric pollutant PM2.5. Besides, compared with the acid soil in southern China, the proportion of ammonia volatilization from calcareous soil after N fertilization in northern China was higher. In the past, although many experimental studies have been carried out on ammonia volatilization in northern China Plain, few have systematically investigated the relationship between ammonia volatilization and fertilizer N used, and the efficacies of different ammonia collection methods, i.e., sponge absorption method and vacuum suction method. In this study, the works of literature on ammonia volatilization during the winter wheat season in northern China published from 1980 to 2018 were collected and the methods of regression analysis and T-test were adopted. Among the 31 papers collected in this study, 17 adopted the sponge absorption method and 14 adopted the vacuum suction method to measure the ammonia volatilized after N fertilization during the winter wheat season. The results showed that under farmer's conventional N fertilization level, the cumulative total ammonia and net ammonia volatilization was exponentially (y=2.64e0.006 6x)and power-functionally(y=0.004 8x1.358 9) correlated with the fertilized N rate, respectively. Correspondingly, the average proportion of net ammonia volatilization to total chemical N applied was (6.27±0.98)%. Under the same N rate at the basal and topdressing stages, the corresponding ammonia volatilization was 58.7% and 41.3% of the total ammonia volatilization in the whole wheat season, indicating the higher contribution of N volatilization at the basal stage, and the importance of mitigation the ammonia volatilization for winter wheat season. At the fertilization rate of 180 kg/hm2 during the winter wheat season, the ammonia volatilization determined by the vacuum suction method and the sponge absorption method was similar. At the fertilization rate of <180 kg/hm2, the ammonia volatilization determined by the sponge absorption method was 0-5% higher than that of the vacuum suction method and at 180-400 kg/hm2, the vacuum suction method was 0-6.9% higher than that of the sponge absorption method, although the statistic differences between these two methods were not significant. This study also found the priming effect of the ammonia volatilization due to chemical N fertilization was 21.8%±3.57%; the net ammonia volatilization determined without considering of priming effect was significantly higher than that determined with considering of priming effect. The mitigation of ammonia volatilization in the winter wheat season should focus on optimizing the N fertilization rate, mainly at the basal fertilization stage, and combined with other farming measures such as drip irrigation and soil mulching). During the field study of ammonia volatilization caused by chemical N fertilization, the priming effect and the overestimate of ammonia volatilization should not be neglected. Differences of NH3 volatilization via the sponge absorption method and the vacuum suction method should also be taken into consideration.

       

    /

    返回文章
    返回