【作者】 串丽敏；

【导师】 赵同科； 刘建玲；

【作者基本信息】 河北农业大学 ， 植物营养学， 2010， 硕士

【摘要】 氮素是植物生长所必需的大量营养元素之一。近年由于农业生产中过量施用氮肥及不合理的管理措施,导致氮素以氨挥发、反硝化及硝酸盐淋溶等途径损失,氮素利用率降低。随着人们生活水平的日益提高,对蔬菜品质的要求也由单纯的满足数量型向质量型转变。研究人员提出了应用生化抑制剂来调控土壤尿素水解和氮素硝化过程,并减少蔬菜硝酸盐过量累积,对控制氮肥污染,提高氮素利用率具有重要意义。本论文采用温室盆栽和土柱淋溶培养试验相结合的方法,研究尿素中添加硝化抑制剂双氰胺(Dicyanamide,DCD)和脲酶抑制剂N-丁基硫代磷酰三胺(N-(n-Butyl) thiophosphoric triamide,NBPT)以及两者不同量的配合施用对油菜产量、硝酸盐及氮素利用的影响,并研究不同施肥量条件下,添加抑制剂后,90cm土柱淋溶液中硝态氮、铵态氮含量和pH值的变化,探索氮素的淋溶损失规律,实现减少氮肥环境风险,提高氮素利用率的目的。试验主要研究结论如下:1.添加硝化/脲酶抑制剂可以提高油菜产量,降低植株硝酸盐累积。当DCD施用量为纯氮量的1%、2%、3%、4%、5%时,可显著增产22.77%~33.50%,同时降低23.87%~30.51%的硝酸盐累积。NBPT在施入纯氮量的0.5%、1.0%、1.5%、2.0%、2.5%水平时,可以显著提高约30%的油菜产量,同时可以降低4.19%~32.63%的硝酸盐累积。DCD与NBPT配合施用,在DCD施用量为纯氮量0.5%,NBPT施用量为纯氮量0.25%时,油菜产量显著提高了46.22%。油菜硝酸盐含量随着两者配合施用量增加,呈现先降低后升高趋势,较低用量配比时已经能够减少硝酸盐累积。2.添加硝化/脲酶抑制剂可以提高氮素利用率。当DCD施用量为纯氮量3%时,油菜氮素利用率可显著提高6.66个百分点。在NBPT0.5%用量时,全氮含量、吸氮量较高,氮素利用率可提高5.65个百分点。DCD与NBPT配合施用,DCD2.0%NBPT1.0%、DCD2.5%NBPT1.25%显著提高了油菜吸氮量和氮素利用率,分别比NPK处理提高3.23和5.48个百分点。3.添加硝化/脲酶抑制剂对氮素残留有一定影响。添加DCD处理,在1%施用水平时显著增加了土壤氮素残留,且随着DCD施用量增加,逐渐降低,且在DCD5%水平时显著降低氮素残留。添加NBPT处理,土壤氮素残留量占尿素施入氮素的45.11%~58.29%,且多数处理比例都在50%以上。NBPT2.0%、NBPT2.5%水平显著降低了氮素残留。两者配施土壤约有44.74%~62.78%的氮素残留。在DCD0.5%, NBPT0.25%时显著降低了尿素在土壤的残留比例。4.低施肥量条件下,DCD可以使硝态氮淋溶达到峰值的时间延缓7天,并使峰值降低。单独添加NBPT处理,前期硝态氮更易发生淋溶,峰值较高,但之后下降很快,并在后期一直保持较低硝态氮浓度。单独添加DCD或者NBPT,不能显著降低硝态氮淋失量,DCD与NBPT混合施用,可以减少土壤淋溶液中硝态氮累积。5.高施肥量条件下,DCD抑制氮素淋失效果较好,而NBPT以及DCD与NBPT配合施用,在后期抑制效果较好。最终三者均可显著降低硝态氮累积淋失量(13.73%、11.61%、17.15%)。6.低施肥量条件下,单施DCD或NBPT,淋溶的无机氮含量增加了13.72%和1.87%,并没有减少无机氮的淋溶损失,还有可能增加原有土壤的氮素淋失,而DCD与NBPT配合施用无机氮含量降低了13.86%。在高施肥量土壤上,DCD、NBPT以及DCD与NBPT配合施用,分别可以降低无机氮损失达7.94%、13.24%、19.53%。7.淋溶液pH与硝态氮浓度呈负相关关系,与铵态氮浓度呈正相关关系。在高低施肥量条件下,淋溶液pH最终约下降了0.07~0.19个单位。在高施肥量条件下,硝态氮浓度达到高峰时,可使pH显著下降0.39个单位。在高施肥量时,DCD、NBPT、DCD与NBPT配施可以避免产生过低和过高的pH变化。更多还原

【Abstract】 Nitrogen is an essential element for plant growth. Nitrogen leaching and runoff losses from arable land because of excessive nitrogen application and unreasonable management measures, which causes contaminations of underground water and surface water, have become a worldwide environmental concern. Vegetables demanded have converted from quantity to quality with the rising of living standard. So scientists have put forward biological inhibitors to control urea hydrolysis and nitrogen nitrification, and to reduce the excessive accumulation of nitrate in vegetables. It plays an important role in control nitrogen fertilizer pollution, also reduce vegetables’nitrate content and enhance the nitrogen use efficiency.This experiment had adopted pot experiment and soil column in greenhouse, to study the effects of nitrification inhibitor Dicyanamide (DCD) and urease inhibitor N- (n-Butyl) thiophosphoric triamide (NBPT) and the two combined application on rape growth and nitrogen utililization, also to study nitrogen migration and transformation when different fertilizer levels applied in 90cm soil column, including nitrate-N, ammonium-N and pH monitored in leaching water.The experiments results showed as follows:1. When nitrification/urease inhibitor added, it could improve the rape yields, and reduce nitrate content in rape. When DCD was applied to urea for the amount of 1%, 2%, 3%, 4%, 5% of nitrogen application, it could significantly increase the biomass of rape and reduce the rape nitrate accumulation by 22.77%~33.50% and 23.87%~30.51%, respectively. Add NBPT to urea could significantly improve the rape yield by 30% and reduce nitrate accumulation highly by 32.63% when was at 0.5%, 1.0%, 1.5%, 2.0%, 2.5%. DCD and NBPT combined application could increase the yield of rape, and when DCD was at 0.5%, NBPT was at 0.25%, it reached significant level by 46.22%. The nitrate in rape showed decreased first and then increased. When the inhibitors were in lower level, they were able to reduce nitrate accumulation.2. When nitrification/urease inhibitor added, it could enhance N use efficiency. When DCD 3% was applied to urea, it could significantly improve nitrogen use efficiency by 6.66 percentage points. When NBPT was at 0.5%, the total N and N uptake were higher than others, and N use efficiency could be improved by 5.65 percentage points. Application of DCD and NBPT mixed, DCD2.0%NBPT1.0%, DCD2.5%NBPT1.25% significantly increased N uptake and nitrogen utilization, respectively, higher compared to NPK by 3.23 and 5.48 percentage points.3. When nitrification/urease inhibitor added, it had some effects on N residue. The nitrate content in soil decreased with DCD applied more. When DCD was at 1%, it could significantly increase N residue, while at 5%, decreased significantly. NBPT resulted in about 45.11% ~ 58.29% N residue in the soil, and most treatments were more than 50%. When NBPT was at 2.0%、2.5%, it could significantly reduced N residue. DCD and NBPT combined application had resulted in about 44.74% ~ 62.78% of the N residue, and when DCD0.5%, NBPT0.25% significantly reduced the proportion of urea in the soil.4. Under lower fertilization conditions, nitrate leaching in DCD treatments could delay the peak time for 7 days throughout the trial period, and also reduce the peak value. Added NBPT alone, more likely to make nitrate leach in early time, and have the higher peak, but then decreased rapidly, and maintained low nitrate concentration in later time. DCD or NBPT added alone, could not significantly reduce the accumulation of nitrate leaching, but the mixed used was able to reduce the nitrate accumulation.5. In the higher fertilizer conditions, DCD throughout the monitoring period had a better effect to retard nitrogen leaching, and NBPT, DCD and NBPT combined application, had a good effect in later period. The three treatments could significantly reduce 13.73%, 11.61%, 17.15% of the cumulative amount of nitrate leaching.6. The single DCD or NBPT application in lower fertilization conditions, inorganic nitrogen content in leaching water increased by 13.72% and 1.87%, and had no reduction on inorganic nitrogen leaching losses, but DCD and NBPT mixed treatment, reduced 13.86%. In higher fertilization conditions, DCD, NBPT and co-application of DCD and NBPT, could reduce 7.49%, 13.24%, 19.53%, respectively.7. pH of leaching water had a negative correlation with the concentration of nitrate content, and showed a positive correlation with the concentration of ammonium nitrogen. Under the low and high fertilizer, the pH dropped by 0.07~0.19 units at the end. When nitrate concentrations reached the peak point under higher fertilizer, it could significantly descend pH by 0.39 units. DCD, NBPT, DCD and NBPT combined application could minimize changes on too low and too high pH under high fertilization.更多还原