基于glomalin蛋白调控的生物有机肥改良滨海盐碱地土壤团聚结构的机制研究

The soil salinization was more and more serious, because of saltwater intrusion, human's unreasonable activities and imperfect drainage facilities. Besides the traditional biological methods such as the development of saline-alkali resistant crop varieties and engineering measures such as brackish water irrigation, the soil fertility of saline-alkali land should be improved. Although previous studies had found that the bio-organic fertilizer could promote the formation of large aggregates in the coastal saline-alkali soil, the original source and formation mechanism of the aggregates were still unknown. Previous studies had proved that in the middle and low saline-alkali land, soil bio-organic fertilizer can significantly increase maize yield, increase soil aggregates, and increase microbial diversity activity. The following research contents are as follows: 1) to clarify the effect of bio-organic fertilizer on the soil agglomeration structure and salt-return process in saline-alkali land; 2) to clarify the influence of bioorganic fertilizer on the structure and function of soil and rhizosphere microbial community; 3) to clarify the role of glomalin-related soil proteins in the formation of soil aggregates; 4) screening and identifying the protein network and regulatory mechanism of bio-organic fertilizer promoting the formation of saline soil aggregates; 5) to clarify the mechanism of bioorganic fertilizer promoting the formation of saline soil aggregates. The significance of this study is not only to reveal the mechanism of bioorganic fertilizer promoting the formation of saline-alkali soil agglomeration, but also to optimize the way of soil improvement in saline-alkali land, providing strong theoretical and technical support for the improvement of coastal saline-alkali land soil.

由于海水倒灌和人类不合理的活动，加之排水设施不完善，导致滨海土壤盐渍化现象日益严重。除传统的研制耐盐碱作物品种等生物手段和微咸水灌溉等工程措施改良外，还需提高盐碱地土壤肥力。前期研究发现生物有机肥可以促进滨海盐碱地土壤大团聚体形成，增加土壤养分，提高土壤微生物活性和多样性，增加春玉米产量。但团聚体原始来源和形成过程机制还未知。因此，本课题将进一步研究以下几个方面：1）明确生物有机肥对盐碱地土壤团聚结构形成及返盐过程的影响；2）明确生物有机肥对土壤和根际微生物群落结构和功能影响；3）明确glomalin相关蛋白在土壤团聚体形成中作用； 4）筛选鉴定生物有机肥促进盐碱土壤团聚体形成的蛋白网络及调控机制；5）明确盐碱地土壤团聚结构形成的机制。本研究意义不仅局限在揭示生物有机肥促进盐碱土壤团聚形成的机制，还将优化盐碱地土壤的改良方式，为滨海盐碱地土壤的改良提供强有力的理论和技术支持。

近年来，由于海水灌溉和人类不合理的开发利用等因素影响，土壤盐渍化导致的土地退化现象日益加重。针对盐碱地土壤易返盐的特点，我们选择施入微生物有机肥的方法改良盐碱地土壤。采用盆栽试验和室内培养试验结合的方法，通过分析植物生长、土壤pH和含盐量等方面的指标评价微生物有机肥改良盐碱地土壤的效果；从土壤物理结构、养分、微生物学三个方面探究微生物有机肥改良盐碱地土壤的机制，为微生物有机肥在盐碱地土壤上的应用提供理论基础和指导方法。.本论文的研究对象为黄河三角洲滨海盐碱地土壤，两年的盆栽试验表明，相同施肥处理和对照的春玉米生物量和产量，随着盐分浓度的升高都表现为逐渐降低。盆栽试验中对照和施入微生物有机肥的处理春玉米生物量随土壤盐分浓度升高减少幅度分别是7.37-26.44%和5.87-10.20%。当土壤盐分浓度 ≤ 1.13 ds m-1时，施入微生物有机肥的处理可以显著提高春玉米总生物量、根部生物量，增大根冠比，产量也随着增加。当土壤盐分浓度小于1.45 ds m-1时，施入微生物有机肥处理土壤有机碳浓度与对照相比提高了18.41-33.95%，差异达到显著水平，大团聚体比例也显著增加，增加幅度为18.51-20.53%，同时泥沙含量显著减少9.95-20.83%。微生物有机肥处理显著增加了大于2000 μm团聚体和小于53 μm的泥沙颗粒有机碳浓度，增加的幅度分别为9.88%-12.30%和8.52%-19.40%。在0.51，1.06，1.44和2.10 ds m-1的四个盐分浓度土壤中，与对照相比，施入微生物有机肥处理可以显著增加土壤有机质和全氮含量，增加的幅度分别为13.90-29.86%和7.79-20.76%。土壤盐分浓度≤ 1.13 ds m-1时，施入微生物有机肥处理显著增加了土壤微生物量碳、氮和微生物量碳氮比，说明施入微生物有机肥处理显著增加了盐碱地土壤的微生物量。施入微生物有机肥的高盐分浓度土壤有7个细菌属(芽孢杆菌，偶氮螺旋菌，伯克霍尔德菌，肠杆菌、微细菌、气单胞菌和中生根瘤菌 (图2-10b)。中盐分浓度土壤有13个细菌属。排名前5的细菌属为枝芽孢菌属，节细菌属，克雷伯菌属，假单胞菌和固氮杆菌。