不同类型短期逆境胁迫对蕉园土壤团聚体组成及酶活性的影响

Effects of Different Short-Term Stresses on Aggregate Compositions and Enzyme Activities of Banana Orchard Soil

采集海南蕉园土壤,通过室内模拟试验研究不同类型环境胁迫对土壤团聚体组成及酶活性的影响。土样经干旱、渍水、酸化和病原菌入侵处理后,采用湿筛法筛分不同粒径团聚体,并进行土壤酶活性和微生物检测。结果发现,除酸化处理土壤>2 mm团聚体比例高于对照外,其余各处理土样>0.25 mm团聚体所占比例与对照相比均显著下降,而<0.25 mm小团聚体比例均显著增加。土壤蔗糖酶、脲酶、磷酸酶和过氧化氢酶等的酶活性与对照相比下降20%~90%。土样经不同处理后细菌数量均显著降低,酸化和病原菌入侵后尖孢镰刀菌数量由原来102 CFU/g分别提高到103 CFU/g及104 CFU/g。Miseq测序结果显示,土壤微生物群落结构也发生了显著变化。结果表明,短期逆境胁迫会影响蕉园土壤结构及功能,降低土壤质量。

Soil samples were collected from a banana orchard in Hainan, the distribution of soil aggregates and enzyme activities were analyzed after the soils were cultured under various conditions such as drought, wet, acidification and pathogen invasion （Fusarium oxysporum）. Soil aggregates （〉2, 2-0.25, 0.25-0.053 and 〈0.053 mm） were separated by wet sieve method. Compared with the control, the proportion of water-stable maeroaggregates （〉0.25 mm） significantly decreased except for the 〉2 mm macroaggregates under acidification, while microaggregates （〈 0.25 mm） increased significantly in all the treatments. The activities of soil invertase, urease, phosphatase and eatalase were reduced by 20% 90%, and bacteria populations were also significantly reduced. Acidification and pathogen invasion significantly increased the numbers of E oxysporum from 10^2 CFU/g to 10^3 CFU/g and 10^4 CFU/g respectively. DNA analyses indicated that soil microbial community structure was also significantly changed. Thus, adverse environmental factors can seriously affect soil quality, e.g., aggregate formation and soil enzyme activities.