西部干旱半干旱煤矿区微生物联合修复机理及其生态响应

The project focuse on the main obstacle factors on coal mining subsidence land reclamation in arid and semi-arid land, such as low soil fertility, the inconsistency of water and fertilizer, reduced root system function, damaged soil structure, which causing land productivity declined and the ecological restoration difficulty and so on, the application of arbuscular mycorrhizal fungi (AMF) and phosphate-solubilizing bacteria (PSB) have been taken as the new breakthrough on coal mining subsidence land reclamation. The high efficient PSB strains has been screened considering the microorganism itself as the strong vitality and adaptive features. Further research on the mechanism of the microbe integration on hard dissolved phosphorus dissolution, phosphorus absorption and transportation, the coordination supply of water and fertilizer on reclaimed soil, root function repair, soil structure improvement. That would reveal the ecological response mechanism with the application of microbe integration on reclaimed subsidence area.Using industrial X-ray CT system to study the repair effects of root system function for microbe integration, the research would get the changing rules of intuitive dynamic properties of the root system though in-situ monitoring and scanning on damaged root. It will be used to reveal the amelioration of soil structure by isotope mark and X-diffraction and glomalin extraction,soil respiration measure method, illustrates the mechanism of microbe integration on subsided land reclamation. It explores the potential of soil fertility fundamentally, improves the rhizosphere environment, accelerates the nutrient biological cycles and achieves the comprehensive ecological effects on microbial reclamation.

针对西部干旱半干旱煤矿区沉陷地复垦存在的主要障碍因子，如土壤肥力低下、水肥不协调供应、根系功能降低、土壤结构破坏等，利用微生物本身所具有强大的生命力与适应性特点，从塌陷地筛选出能够高效解磷的微生物，将本地优势丛枝菌根真菌与解磷微生物联合作为采煤塌陷地复垦新突破口。深入研究该微生物联合对难溶性磷的溶解、吸收与运输机理，复垦土壤的水肥供应，拉伤根系功能的修复，土壤结构改良，并综合应用于塌陷区复垦地来系统揭示其生态响应机制。利用X-射线工业CT和CI-600根系监测系统来动态监测微生物联合对根系功能的修复作用，通过对受损根系的活体和原位监测与扫描来直观动态地获得根系形态特性的变化规律，采用同位素标记、X-衍射、球囊霉素提取、土壤碳通量和光合作用监测等测定方法来揭示其对土壤结构改良作用，阐明微生物联合对塌陷地修复的机理及其生态响应规律，为西部干旱半干旱煤矿区生态修复奠定技术基础。

本研究针对西部干旱半干旱煤矿区沉陷地复垦存在的主要障碍因子，利用粉煤灰中的磷元素，分离筛选出了两株解磷细菌CA04和SL05，其对粉煤灰基质有显著的改良作用，能够促进植物生长及对粉煤灰中难溶性磷的吸收利用，增加根际细菌和真菌的数量。解磷细菌与丛枝菌根真菌和根瘤菌联合应用于粉煤灰基质中，三种菌混合接种均比单一接菌更能提高植物的生物量。同时，通过由根室、菌根室和菌丝室组成的三室分根系统，确定了影响微生物与外源磷协同作用对伤根植物的生态修复效应的主导因子和机制。结合矿区土壤难溶磷含量高的特点，模拟微生物与外源磷协同作用对根系受损玉米的修复作用。其次，在野外试验的基础上，进行室内盆栽试验，利用13C脉冲标记法研究发现AM真菌与复垦地的土著菌产生协同效应，提高紫穗槐叶片可溶性糖含量，促进植物叶片光合固碳；同时，AM真菌可以影响了植物-土壤碳分配，提高玉米叶片和根系中13C分配量，降低茎秆和土壤中13C分配量，增加土壤碳沉积量。此外，AM真菌提高了樟子松人工林灌木层物种多样性，而降低草本层物种多样性，提高了沙棘和文冠果人工林的草本植物群落稳定性和物种多样性及其均匀，促进了生态的演变进程。此外，不同植被类型下，接种AM真菌的根际土壤养分和土壤酶活性均显著高于对照区土壤。不同植被类型下和接菌AMF影响土壤细菌群落的组成，接种AMF可以影响根际土壤富营养微生物菌群（变形菌门）的相对丰度，从而改变土壤养分含量。接种AM真菌显著提高了根际土壤的含水率、总球囊霉素和易提取球囊霉素，而速效磷和速效钾的含量显著降低。P-RDA分析表明土壤微生物活动受土壤因子的不同程度影响，且AM真菌土壤中氮捕获酶相关，并对煤矿塌陷区土壤氮素产生影响。本研究阐明了微生物联合对塌陷地修复的机理及其生态响应规律，为西部干旱半干旱煤矿区生态修复和土地复垦提供了理论依据，为促进矿区经济与环境的协调可持续发展提供了技术支撑。