Adaptive management of arbuscular mycorrhizal fungi (AMF) provides a new option for sustainable agriculture. Previous studies showed that the functional role of AMF was frequently dependent on soil moisture and planting densities in the semiarid environment. However, a systematic quantitative analysis of the effects of AMF inoculation on crop productivity and soil quality needs to be investigated. Therefore, a 2-year field experiment was conducted to test the inoculation effects of AMF (Funneliformis mosseae) on wheat (Triticum aestivum L.) productivity and soil quality in the semiarid Loess Plateau under two water regimes (irrigated and non-irrigated) with seven plant densities in year 2017 and 2018. Our results showed that in the non-irrigated treatment, inoculation with AMF greatly increased dryland wheat aboveground biomass, crop productivity, water use efficiency, rhizosphere soil organic carbon, soil organic carbon to total nitrogen ratio, microbial biomass carbon to nitrogen ratio, and microbial biomass carbon and nitrogen (P < 0.05) compared to the non-inoculated treatment. For example, compared with non-inoculated plants, the grain yield in the non-irrigated but inoculated plants increased by 59 ± 28% in 2017 and 36 ± 2.8% in 2018, and the water use efficiency for grain increased by 53 ± 26% and 25 ± 12% in 2017 and 2018, respectively. However, the different results were observed under irrigated conditions. In the irrigated treatment, AMF inoculation had a slightly positive effect on grain yield and soil quality at low plant density but was negative at higher plant densities. Here we demonstrated for the first time that AMF inoculation significantly improved wheat productivity and soil quality, while its effects were conditionally density- and moisture-dependent. Therefore, optimizing AMF addition is an effective measure for sustainable agricultural development and provides a novel solution for the management of soil degradation management in the semiarid area of the Loess Plateau.

丛枝菌根真菌（AMF）的自适应管理为可持续农业提供了新的选择。先前的研究表明，AMF的功能性作用通常取决于半干旱环境中的土壤水分和种植密度。但是，需要研究AMF接种对作物生产力和土壤质量的影响的系统定量分析。因此，2年大田试验，以测试AMF（接种效果Funneliformis霉）小麦（普通小麦L.）半干旱黄土高原在两种水质模式下（灌溉和非灌溉）在2017年和2018年的生产力和土壤质量分别为7种植物密度。我们的结果表明，在非灌溉处理中，AMF接种大大增加了旱地小麦地上生物量，作物生产力，水分利用效率，根际土壤有机碳，土壤有机碳与总氮之比，微生物生物量碳与氮之比以及微生物生物量碳与氮（P <0.05）与未接种的治疗相比。例如，与未接种植物相比，未灌溉但已接种植物的谷物产量在2017年增加了59±28％，在2018年增加了36±2.8％，谷物的水分利用效率增加了53±26％在2017年和2018年分别为25％和12％。但是，在灌溉条件下观察到了不同的结果。在灌溉处理中，AMF接种在低植物密度下对谷物产量和土壤质量有轻微的积极影响，而在较高植物密度下则不利。在这里，我们首次证明了接种AMF可以显着提高小麦的生产力和土壤质量，而其影响则取决于密度和水分。因此，