玉竹连作对土壤微生物区系的影响

连作导致玉竹产量及品质下降,严重威胁玉竹的生产,对玉竹连作模式下相关土壤生态指标进行研究,对于认识和克服连作障碍具有十分重要的意义。为揭示玉竹连作对根际土壤微生态的影响,采用稀释平板测数法和最大或然数法研究了玉竹连作3年根际土壤和种植1年玉竹的根际土壤3大类群土壤微生物及主要功能微生物的数量变化。结果表明:连作对玉竹根际土壤微生物区系构成明显影响,其细菌数量较对照土壤降低了12.4%,放线菌数量降低了13.2%,真菌数量则增加了239%,好氧自生固氮菌数量降低了36.3%,氨化细菌数量降低了48.6%,硝化细菌数量变化不大,有机磷细菌数量增加了12.1%,无机磷细菌数量降低了71.1%。说明连作不利于玉竹根际土壤微生态质量的维持。

Influence of Continuous Cropping Mode of Polygonatum odoratum on Soil Microflora

Abstract: Continuous cropping obstacles cause a serious threat to the yield as well as the quality of Polygonatum odoratum cultivation. Meanwhile, it''s significant to study the soil ecological index after continuous cropping and then to realize and overcome the continuous cropping barrier. Aiming this problem, the rhizosphere soil of Polygonatum odoratum after 3-year continuous cropping and the rhizosphere soil of Polygonatum odoratum after 1-year cropping were used as testing samples. The numbers of the three community of microorganism (bacteria, actinomycetes and fungi) and major functional microorganisms were analyzed by the spread plate method and most-probable-number method (MPN). The results showed that the microflora of the rhizosphere soil was strongly influenced by continuous cropping. Compared with the soil after 1-year cropping, the population of bacteria and actinomycetes in continuous cropping soil has decreased by 12.4% and 13.2%, respectively. The population of fungi increased by 239%. The population of aerobic azotobacteria and ammonifier reduced by 36.3% and 48.6%, respectively. The population of nitrobacteria changed little. The population of organic phosphobacteria increased by 12.1%. The population of inorganic phosphobacteria decreased by 71.1%. The results showed that continuous cropping had a disadvantage of maintaining the micro-ecological environment on the rhizosphere soil of Polygonatum odoratum.