Assessment of Arbuscular Mycorrhizal Fungal Inoculants for Pulse Crop Production Systems

市售丛枝菌根（AMF）接种剂的引入为脉冲作物生产系统的应用带来了巨大的希望。已知有效的AMF关联可增强对相对不动营养素（如磷和各种微量营养素）的吸收，并与提高抗旱性、抗病性、氮吸收和增强生物二氮固定有关。目前，AMF接种剂大规模释放的潜在后果尚不清楚，假设AMF接种最好是有益的，或最坏的是良性的。然而，已知AMF物种在促进生长的能力方面存在差异，从共生到寄生，取决于寄主植物以及环境气候和土壤条件。重要的是，几乎所有市售的AMF接种剂都含有球囊菌。这个品种是首选的接种工业，因为它孢子容易产生，适合大规模生产。容易产生孢子的AMF物种是否有可能取代其他天生更好的生长促进剂物种？考虑到持久的、积极产孢的AMF物种可能对有益的本地AMF物种和非目标寄主作物产生潜在影响，我们必须确信，引入的物种确实是土壤微生物群落的理想补充；它是一种有效的生长促进剂；它不会取代自然产生的AMF，后者本质上是更好的生长促进剂；而且对未来轮作中种植的非目标寄主作物也不会产生负面影响。该项目的目标是：1)评估市售AMF接种剂与从草原土壤中分离的本土AMF相比的促生长特性（包括与根瘤菌接种剂和二氮固定剂的协同作用）；2)评估AMF接种对本地AMF种群数量和定殖成功的影响；3)研究土壤和气候/天气对引进AMF持续存在的影响；4)研究AMF接种率对促进生长和与本地AMF竞争的影响。

The introduction of commercially available arbuscular mycorrhizae (AMF) inoculants holds significant promise for use in pulse crop production systems. Effective AMF associations are known to enhance uptake of relatively immobile nutrients such as phosphorus and various micronutrients, and are implicated in improved drought resistance, disease tolerance, nitrogen uptake, and enhanced biological dinitrogen fixation. Currently, the potential consequences of large-scale release of AMF inoculants are not known, and it is assumed that AMF inoculation will be beneficial at best, or benign at worst. However, AMF species are known to differ in their ability to promote growth, ranging from mutualistic to parasitic, depending on host plant, and ambient climatic and soil conditions. Importantly, virtually all commercially available AMF inoculants contain the species Glomus intraradices. This species is preferred by the inoculant industry because it sporulates readily and is amenable to large-scale production. Does an AMF species that sporulates readily have the potential to displace other species that are inherently better growth promoters? Given the potential impact that a persistent, aggressively sporulating AMF species might have on beneficial indigenous AMF species and non-target host crops, we must be confident that the introduced species is indeed a desirable addition to the soil microbial community; that it is an effective growth promoter; that it will not displace naturally occurring AMF that are inherently better growth promoters; and there will be no negative consequences to non-target host crops grown in the future rotation. The objectives of this project are to: 1) assess the growth promotion characteristics (including synergies with rhizobial inoculants and dinitrogen fixation) of commercially available AMF inoculants as compared to indigenous AMF isolated from prairie soils; 2) assess the impact of AMF inoculation on populations and colonization success of indigenous AMF; 3) examine the impact of soil and climate/weather on the persistence of introduced AMF; and 4) examine the influence of AMF inoculant rate on growth promotion and competition with indigenous AMF.