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通过对内蒙古草场田间试验,研究水和氮调控对草场土壤微生物生物量、土壤呼吸、土壤微生物活性以及微生物群落结构的影响,试验按照裂区设计,主区为降水量(正常降水、增加降水180mm/年),副区为氮素施用量(0、50、100、150kg/hm~2)。结果表明:土壤微生物碳、氮量随施氮量增加而降低,施氮量为150kg/hm~2时最低,分别为105.23mg/kg、13.85mg/kg;增加降水会缓解下降趋势,50kg/hm~2施氮量时数值显著提升50.6%、59.4%;随施氮量增加,土壤基础呼吸、土壤诱导呼吸逐渐降低,CAI、呼吸商逐渐升高,施氮量最大时分别下降30.95%、98.02%,升高73.63%、63.74%,增加降水后各指标均有明显提升,土壤基础呼吸、诱导呼吸增加显著;随施氮量增加,土壤DHA酶、PRO酶、Acld PME酶、Alkaline PME酶逐渐降低,增加降水会使各酶升高;细菌、真菌、丛枝菌根真菌和厌氧菌相对丰度分别在施氮量为100、100、0、150kg/hm~2时最高,增加降水后使厌氧菌、丛枝菌根真菌分别降低11.07%、增加20.59%。
Through field experiments in Inner Mongolia grassland, the effects of water and nitrogen on grassland soil microbial biomass, soil respiration, soil microbial activity and microbial community structure were studied. According to the design of the fractured area, the main area is precipitation (normal precipitation, precipitation increase 180mm / Year), the subzone is nitrogen application rate (0,50,100,150kg / hm ~ 2). The results showed that the soil microbial biomass C and N decreased with the increase of nitrogen application rate, and the lowest was 150.23mg / kg and 13.85mg / kg when the nitrogen application rate was 150kg / hm ~ 2. The increase of precipitation would alleviate the downward trend, The values of nitrogen and nitrogen increased significantly by 50.6% and 59.4%, respectively. With the increase of nitrogen application rate, soil-based respiration and soil-induced respiration decreased gradually, CAI and respiratory quotient increased gradually. 98.02%, increased by 73.63% and 63.74%, respectively. After adding precipitation, the indexes increased significantly, and the soil respiration and induced respiration increased significantly. With the increase of nitrogen application rate, soil DHA, PRO, Acld PME and Alkaline PME The relative abundance of bacteria, fungi, arbuscular mycorrhizal fungi and anaerobic bacteria were the highest when the nitrogen application rates were 100, 100, 0, and 150 kg / hm ~ 2, respectively, and the precipitation was increased After the anaerobic bacteria, arbuscular mycorrhizal fungi were reduced by 11.07%, an increase of 20.59%.