秸秆还田对土壤微生物种群数量及小麦茎基腐病的影响

为了探索秸秆还田对土壤微生物种群数量及小麦茎基腐病的影响，本研究采用稀释平板计数法分析了秸秆还田和未还田小麦根际土壤中的细菌、真菌、放线菌的数量，并系统调查了小麦茎基腐病的发生情况。结果表明，秸秆还田后小麦根际土壤中细菌、真菌、放线菌的数量明显提高，小麦茎基腐病的发生比未还田的严重。秸秆还田后，在返青期、拔节期、孕穗期、扬花期、成熟期五个生育期中，茎基腐病的发病率均比未还田区的发病率高，分别高出12.00%、13.00%、17.50%、17.00%和16.00%，茎基腐病的病情指数比未还田区分别高出3.38、5.28、7.37、8.25和8.13。秸秆还田后，土壤中的微生物数量相比未还田土壤中的显著增加，真菌的增长幅度最大，在小麦五个生育期中分别比未还田土壤中的真菌增长591.32%、373.63%、212.62%、285.74%、373.95%。因此，秸秆还田后，增加了土壤微生物数量，加重了小麦茎基腐病的发生。

Straw Returning Affects Soil Microbial Population and Wheat Crown Rot

To explore the effect of straw returning on soil microbial population and wheat crown rot, the number of fungi, bacteria and actinomycetes in the rhizosphere soil under straw returning and non- returning was analyzed by dilution and separation method. The occurrence of wheat crown rot was investigated. The results showed that the number of bacteria, fungi and actinomycetes in wheat rhizosphere soil increased significantly after straw returning, and the occurrence of wheat crown rot was more serious than that of non-returning. After the straw was returned to the field, the incidence of wheat crown rot was higher than that in the non-returning area during the greening stage, jointing stage, booting stage, flowering stage and maturity stage, the incidence of wheat crown rot was 12.00%, 13.00%, 17.50%, 17.00% and 16.00% higher respectively, and the disease index of wheat crown rot was 3.38, 5.28, 7.37, 8.25 and 8.13 higher than that of the non-returning field, respectively. After the straw was returned to the field, the amount of microorganisms in the soil increased significantly compared with that in the non-returning soil, and the fungus increased most significantly. In the five growth stages of wheat, the growth of fungi in the soil was 591.32%, 373.63%, 212.62%, 285.74% and 373.95% higher than that of the non-returning field, respectively. Therefore, after the straw is returned to the field, the amount of soil microorganisms is increased, which aggravates the occurrence of wheat crow rot.