深松对乌拉尔甘草根际土壤养分以及微生物群落功能多样性的影响

通过大田试验和室内分析相结合,研究了深松对乌拉尔甘草根际土壤养分和微生物群落功能多样性的影响,以期为乌拉尔甘草人工种植地土壤耕作措施优化和土壤环境改良提供依据。结果表明,与未深松(常规耕作)处理相比,深松处理对乌拉尔甘草根际土壤0—20 cm耕层土壤养分含量无显著性影响,可显著提高乌拉尔甘草根际土壤20—40 cm耕层有机质、全氮、全磷和全钾的含量,分别提高了60.8%、65.3%、48.9%和86.8%;明显增加了0—20 cm和20—40 cm耕层细菌、真菌和放线菌的数量(P0.05),3种类型的微生物数量均呈现出上层大于下层,深松大于未深松的变化趋势。在156 h的微生物温育期内,深松处理下不同土层的平均颜色变化率(AWCD)均显著高于未深松处理,并显著提高了AWCD的利用率(72 h,P0.05),较未深松分别提高了35.5%和130.8%。与未深松处理相比,深松处理显著提高了土壤微生物的多样性指数(H、S、D)。主成分分析(PCA)表明,深松优化了乌拉尔甘草根际土壤微生物的群落组成;聚合物、羧酸类化合物、氨基酸和碳水化合物是深松处理下根际土壤微生物利用的主要碳源。总而言之,深松处理显著提高乌拉尔甘草根际土壤养分含量、微生物数量和微生物多样性指数,改变了微生物群落功能多样性,造成这种差异的主要原因可能是深松改变了土壤耕层结构,改善了微生物的生存环境。因此,深松对乌拉尔甘草人工种植地土壤质量的改良有积极作用。

Effect of subsoiling on soil nutrient and microbe functional diversity of Glycyrrhiza uralensis rhizospheres

As a fundamental soil component,soil microorganisms can sensitively,timeously,and accurately reflect the status of the change of soil quality and reveal the condition of soil fertility and improvement,which are important indicators of soil quality.At present,subsoiling technology is considered a soil conservation-tillage technology,which can change the soil structure and influence the soil microbial community.Therefore,the effect of tillage methods on microbes in soil ecosystems is being well studied globally.However,little is known about effect of subsoiling on soil nutrients and the functional diversity of microbial communities in rhizosphere soil of Glycyrrhiza uralensis.The purpose of this study was to provide the basis for improving tillage practices and soil environmental condition of licorice.Compared to conventional methods,Biolog technology can effectively provide useful information on soil microbial community functional diversity.Therefore,in this study,two treatments,including rotary tillage (CK) and subsoiling,were conducted in licorice planting land.Using field experiments and laboratory analysis,the effect of subsoiling on soil nutrients and the functional diversity of microbial communities in rhizosphere soil of G.uralensis was determined.The results showed that the effect of subsoiling on soil nutrients in the 0-20 cm depth of rhizosphere soil of G.uralensis was not significant,but greatly improved the total nitrogen (TN),phosphorus (TP),and potassium (TK) contents in the 20-40 cm depth of rhizosphere soil of G.uralensis(which increased by 60.8,65.3,48.9,and 86.8%,respectively).Meanwhile,the number and abundance of bacteria,fungi,and actinomycetes within the 0-20 and 20-40 cm depths of rhizosphere soil of G.uralensis was significantly increased (P < 0.05).The quantity of three types of microorganisms present in the upper layer was greater than in the lower layer,and was greater in the subsoiling than non-subsoiling.After 156 h of microbial incubation,Average Well Color Development (AWCD) of different soil layers of subsoiling treatments were obviously higher than those of non-subsoiling treatments,and subsoiling treatment significantly improved the utilization of AWCD (72 h,P < 0.05),by 35.5 and 130.8% in the upper and lower soil layers,respectively.Compared with the non-subsoiling treatment,subsoiling significantly increased the microbial diversity index (such as the Shannon Index (H),Substrate Richness Index (S),and Simpson''s Dominance Index (D)).A principal component analysis (PCA) showed that subsoiling treatment could optimize microbial community composition in licorice rhizosphere soil;polymers,carboxylic acids,amino acids,and carbohydrates were primary carbon sources of rhizosphere soil microbes in subsoiling areas.Overall,the nutrient content of soil,the number of microbes,and the microbial community diversity index were obviously improved by subsoiling in licorice rhizosphere soil,and the microbial community functional diversity was changed.The arable layer soil structure was enhanced,and therefore the survival of microorganisms was improved by subsoiling.Therefore,subsoiling treatment could effectively improve the quality of rhizosphere soil of G.uralensis.