溶磷菌剂对施磷复垦土壤无机磷形态及油菜磷吸收的影响

  目的  通过分析攀西高原不同轮作模式对土壤肥力和phoD基因群落结构的影响，以期深入认识该生境下土壤磷素循环机制，建立合理的轮作制度。  方法  以攀西高原五种不同轮作制度下的休闲期土壤为研究材料，通过化学分析和高通量测序技术对土壤理化性质以及土壤中phoD基因群落结构与多样性进行研究。  结果  不同轮作制度处理下，相较于撂荒处理，土壤有效磷含量显著提高，全氮、碱解氮、有机碳含量显著降低（P < 0.05）。土壤中酸性磷酸酶活性（Acid phosphatase, ACP）显著高于碱性磷酸酶（Alkaline phosphatase, ALP）和中性磷酸酶（Neutral phosphatase, NP），且在大麦－烤烟轮作制度中最高（13358 U g⁻¹）。就phoD基因的shannon多样性指数而言，在大麦－烤烟轮作制度下最高，而在苦荞－烤烟轮作下最低。
不同轮作制度下phoD群落结构差异明显，变形菌门（Proteobacteria）、放线菌门（Actinobacteria）是不同轮作模式的主要门类，慢生根瘤菌(Bradyrhizobium)为主要优势属。冗余分析显示，有机碳、pH是该生境下驱动phoD基因群落结构变化的重要理化因子。  结论  与撂荒相比，轮作明显改变了土壤肥力和磷酸酶活性，形成了不同的土壤phoD基因群落结构。五种轮作制度中以苦荞－烤烟轮作对phoD基因多样性指数影响最为显著，大麦－烤烟轮作对土壤养分含量和碱性磷酸酶活性影响最大。

Prospects for using soil microorganisms to improve the acquisition of phosphorus by plants

  Objectives  By analyzing the effects on soil fertilization and phoD gene community structure and diversity under different crop rotation systems in Panxi plateau, this paper is aimed to further understand the soil phosphorus (P) circulation mechanism in plateau habitat and to establish a reasonable crop rotation system.  Methods  In this study, the fallow non-rhizosphere soils under five different crop rotation systems in Panxi plateau were selected as the research objects. Using chemical analysis and high-throughput sequencing technology, the physical-chemical properties, the phoD community structure and gene diversity of soil were investigated.  Results  Under different crop rotation systems, soil available P content increased significantly compared with barely roots. However, total nitrogen (TN), alkali-hydrolyzed nitrogen (AN) and soil organic carbon (SOC) contents decreased obviously(P < 0.05). Acid phosphatase activity (ACP) was higher than alkaline phosphatase (ALP) and neutral phosphatase(NP) in soil, which was the highest under Maize-flue-cured tobacco crop rotation system (13358 U g⁻¹).
Shannon diversity index of phoD gene was the highest under Maize-flue-cured tobacco crop rotation system and lowest under buckwheat (Fagopyrum tataricum)-flue-cured tobacco crop rotation system. phoD gene community structure had obvious differences under different crop rotation systems. Proteobacteria and Actinobacteria were the main phylums under different crop rotation systems, and Bradyrhizobium was the mutual advantage species in all patterns. RDA analysis showed that SOC and pH were the main factors stimulating the development of phoD gene community structure.  Conclusions  Compared with barely roots, crop rotation systems changed soil fertilization and phosphatase activity obviously and developed different phoD gene community structure of soil. In five crop rotation systems, Buckwheat (Fagopyrum tataricum)-flue-cured tobacco crop rotation system had the most significant effect on phoD gene diversity index and Maize-flue-cured tobacco crop rotation system had the most significant effect on soil fertilization contents and ALP activity.