长孢被孢霉改善砂姜黑土胀缩与贫瘠障碍的作用机制

The lime concretion black soil with swelling-shrinkage properties and low fertility has negative effects on agricultural production and food security in the Huang-Huai area. Since soil microbes are involved with soil structure formation, nutrient turnover and soil organic matter accumulation, they play key roles in improving physical structure and fertility in the lime concretion black soil. The potential of specific microbes in soil improvement needs to be explored. We isolated a novel Mortierella elongata (M. elongata) SX in the lime concretion black soil, and found that M. elongata SX significantly improved the soil swelling-shrinkage and fertility. However, how M. elongata SX improves the soil swelling-shrinkage and fertility in the lime concretion black soil remains unclear. In this project, we will conduct pot experiment and field experiment, and use some technologies including scanning electron microscope, high-throughput sequencing, solid-state 13C nucleic magnetic resonance, etc. Our aim is to reveal the mechanisms of M. elongata SX improving the soil swelling-shrinkage and fertility by facilitating soil aggregation, mediating bacterial community, and accelerating straw decomposition in the lime concretion black soil. Our study is anticipated to provide certain theoretic basis and technical support for improvement of the lime concretion black soil in the Huang-Huai area.

砂姜黑土胀缩与贫瘠障碍严重影响黄淮片区农业生产和粮食安全。土壤微生物作为土壤结构形成、养分转化及有机质积累的关键参与者，必然对砂姜黑土结构物理性质及肥力改良起重要作用，关键特定微生物的改良潜力亟待研究与挖掘。我们在淮北平原砂姜黑土中分离筛选出一株新型的长孢被孢霉Mortierella elongata SX，发现长孢被孢霉Mortierella elongata SX能明显改善砂姜黑土胀缩与贫瘠状况，然而作用机制尚不清楚。本项目拟通过盆栽实验和田间实验，利用扫描电镜、13C核磁共振、高通量测序等技术，研究长孢被孢霉Mortierella elongata SX如何通过菌丝促进土壤团聚化、通过菌丝调节土壤细菌群落、通过促进秸秆腐解来改善砂姜黑土胀缩与贫瘠障碍的作用机制，为黄淮片区砂姜黑土改良提供一定的理论基础与技术支持。

砂姜黑土胀缩与贫瘠障碍严重制约了作物产能的提升。本研究解析了被孢霉对砂姜黑土障碍消减的作用及其机制，并评价了被孢霉菌剂的田间实施效果。研究发现被孢霉主要通过促进秸秆降解转化、土壤养分周转活化及调节微生物群落结构，有利于土壤结构改良及肥力提升，从而改善砂姜黑土胀缩与贫瘠障碍。长孢被孢霉接种（也包括高山被孢霉及两种被孢霉混合接种）促进秸秆降解，增加秸秆中烷氧碳比例而降低羰基碳比例；下调秸秆表面微生物的氨基酸、碳水化合物、萜类、多聚酮类代谢等基因而上调多糖生物合成等基因；提高土壤碳氮磷养分活化及其有效性，调节土壤β-葡糖苷酶、N-乙酰-β-氨基葡糖苷酶及碱性磷酸酶活性；转变根际微生物多样性和群落组成，引起珞珈苍黄色杆菌、不动杆菌、芽孢杆菌、肠杆菌等细菌和被孢霉菌、腐质霉菌、丛赤壳菌、毛壳菌等真菌的丰度比例变化，这些微生物可高效代谢周转复杂有机物质，进一步提高砂姜黑土有机质的周转及碳氮磷养分的活化；在黄淮南片砂姜黑土区（安徽太和）开展田间实验，发现田间水热波动条件下被孢霉菌剂对砂姜黑土碳氮磷养分有效性及作物生长的改良效果不明显，被孢霉菌剂有待进一步优化且其田间实施效果有待深入论证评估。研究可为砂姜黑土改良及障碍消减提供一定理论支撑。