中文摘要：

【目的】高养分浓度可能对土壤的碳氮转化和微生物特性产生显著影响。研究高养分浓度下添加葡萄糖对土壤中碳氮的转化调控及其微生物变化特征,可为正确认识特殊条件下养分转化过程特性,提出提高氮素利用效率的措施提供科学参考。【方法】采集中国亚热带地区典型的水稻土样品,设置不同硫酸铵用量和葡萄糖添加量处理,布置室内培育试验,研究了不同处理下土壤中NH4＋-N、NO3--N、矿质氮、微生物生物量及微生物群落功能多样性变化。【结果】与不添加葡萄糖处理相比,高硫酸铵用量处理下,添加不同浓度葡萄糖处理NH4＋-N、NO3--N和矿质氮变幅分别为-4.3%—10.2%、-8.0%—41.8%和-3.9%—10.4%,而微生物量碳显著增加了89.6%—126.7%,微生物量氮增加了11.5%—109.0%。中等硫酸铵用量处理下,添加葡萄糖处理NH4＋-N、NO3--N和矿质氮浓度变幅分别为-7.5%—5.8%、6.1%—58.3%和-7.2%—49.4%;微生物量碳氮也有增大趋势。BIOLOG分析显示,高、中硫酸铵用量处理下,AWCD值、Shannon、Simpson和McIntosh指数一直处于较低水平。与常规硫酸铵用量处理相比,仅添加葡萄糖和常规硫酸铵用量下添加葡萄糖后,NH4＋-N、NO3--N和矿质氮浓度显著降低了17.3%—29.0%、21.4%—92.9%和18.8%—45.9%,微生物量碳、氮没有显著增加,AWCD值和微生物功能多样性指数水平较高。葡萄糖及硫酸铵对土壤微生物量碳和AWCD值的影响存在交互作用。【结论】较高的养分浓度下添加葡萄糖,调节了土壤C/N比,土壤微生物活动增强,提高了氮素的生物固持效率,降低了土壤中无机氮的含量。在当前大量施用无机氮肥背景下,尤其要重视有机无机肥配合,调控氮素转化过程,降低氮素损失风险。

英文摘要：

【Objective】High nutrient concentration may have a significant impact on soil carbon and nitrogen transformation and microbial characters.Soil carbon and nitrogen transformation and microbial characters of glucose addition at high nutrient concentration of the fertilizer were determined for understanding of the transformation process of the special characteristics of nutrient conditions and for proposing scientific measures to improve nitrogen use efficiency.【Method】Paddy soils were selected in subtropical region of China.Changes of NH4＋-N,NO3--N,inorganic N,microbial biomass,microbial functional diversity were measured by an incubation experiment through setting different amount of ammoniums sulfate and glucose treatments.【Result】Compared with using ammonium sulfate treatments,adding glucose at high concentration of ammonium sulfate treatments,NH4＋-N,NO3--N and inorganic N contents ranged-4.3%-10.2%,-8.0%-41.8% and-3.9%-10.4% respectively.Microbial biomass carbon was increased significantly by 89.6%-126.7%,while microbial biomass nitrogen was increased by 11.5%-109.0%.NH4＋-N,NO3--N and inorganic N contents of adding glucose at moderate concentration of ammonium sulfate ranged-7.5%-5.8%,6.1%-58.3% and-7.2%-49.4% respectively.Microbial biomass carbon and nitrogen also showed an increasing trend.BIOLOG analysis showed that AWCD value,Shannon,Simpson and McIntosh indices were at a low level at high and moderate concentrations of ammonium sulfate.Glucose addition alone and glucose addition with conventional concentration of ammonium sulfate,NH4＋-N,NO3--N and inorganic N contents were decreased by 17.3%-29.0%,21.4%-92.9% and 18.8%-45.9%,respectively.Microbial biomass carbon and nitrogen were not significantly increased.AWCD value,Shannon,Simpson and McIntosh indices were higher.There were interactive effects on microbial biomass carbon and AWCD values of adding glucose and ammonium sulfate.【Conclusion】Adding glucose at higher concentration of ammonium sulfate increased nitrogen immobilization ef