石灰联合碳铵熏蒸对连作香蕉生长和根际微生物群落结构的影响

摘 要：由于长期连作导致香蕉枯萎病大量爆发，造成香蕉种植面积锐减，已严重影响海南香蕉产业的发展，因而急需寻求能够缓解或克服香蕉连作障碍的有效措施。本实验旨在探究使用绿色土壤熏蒸剂对长期连作蕉园的香蕉枯萎病的防控效果，特别是对植株生长发育、土壤化学性质和根际微生物区系的影响。田间试验共设置两个处理：石灰碳铵熏蒸处理（LAB）和对照处理（CK）。结果表明: LAB处理可以显著降低香蕉枯萎病发病率，与CK处理相比两季分别降低40%和46.62%，显著增加香蕉亩产量，与CK处理相比两季分别增产45.56%和75.99%。LAB处理可以显著提高土壤pH，改善土壤酸化，使酸性土壤维持中性水平，同时，增加土壤有机质含量，并且显著提高土壤速效磷（两季分别提高28.33%和89.14%）和速效钾含量（23.92%和38.67%）。并且LAB处理明显改变香蕉根际微生物群落结构，可以显著降低变形菌门和子囊菌门相对丰度，显著增加放线菌门等相对丰度，同时显著降低病原菌镰刀菌属相对丰度，并且显著提高部分土壤拮抗菌属的相对丰度，如链霉菌属、红球菌属和曲霉属。因此，石灰碳铵熏蒸有效改善香蕉根际微生物群落结构，有效防控香蕉枯萎病的发生并促进其植株生长。

Effects of lime-ammonium bicarbonate fumigation on banana growth and structure of rhizosphere microbial community in a continuous cropping system

Abstract: Hainan Province is the main banana growing and processing region in China. However, due to continuous cropping, the Fusarium wilt disease seriously outbreaks, resulting in production losses and impairing the development of banana industry in that region. Therefore, the purpose of this paper was to find an effective measure to m itigate or overcome the obstacle of banana continuous cropping systems. A field experiment was conducted to evaluate the effectiveness of green soil fumigation agent on the prevention and control of Fusarium wilt disease in those banana gardens with long-term continuous cropping systems, especially on the growth and development of plants, chemical property of soil and rhizosphere microflora. Two treatments were selected in field experiment: The lime-ammonium bicarbonate fumigation (LAB) and the control check (CK). Results indicated that compared with CK, LAB treatment significantly decreased the incidence of diseased plants by 40% and 46.62%, and significantly increased the yield by 33.01% and 75.46% respective in two seasons. Meanwhile, LAB treatment could significantly improve soil pH, mitigate soil acidification, maintain acid soil at a medium level, increase soil organic matter, and significantly increase soil available phosphorus by 28.33% and 89.14%, and rapidly available potassium by 23.92% and 38.67% respective in two seasons. Moreover, LAB treatment significantly changed the structure of rhizosphere microbial community, significantly decreased the relative abundance of Ascomycota and Proteobacteria, significantly increased the relative abundance of Actinobacteria. Furthermore, LAB treatment significantly decreased the relative abundance of Furarium, and significantly increased the relative abundance of soil antagonist microbes, such as Streptomyces, Rhodococcus and Aspergillus. Hence, it was indicated that using lime-ammonium bicarbonate fumigation could effectively improve the structure of rhizosphere microbial community, efficiently prevent and control the occurrence of Fusarium wilt disease and promote the growth of plants.