Hansen Jeremy C, Schillinger William F, Sullivan Tarah S, Paulitz Timothy C
Northwest Sustainable Agroecosystems Research Unit, USDA-Agricultural Research Service, Washington State University, Pullman, WA, United States.
Department of Crop and Soil Sciences, Washington State University, Pullman, WA, United States.
Front Microbiol. 2019 Jul 11;10:1488. doi: 10.3389/fmicb.2019.01488. eCollection 2019.
With increasing canola ( L.) acreage in the Inland Pacific Northwest of the USA, we investigated the effect of this relatively new rotational crop on soil microbial communities and the performance of subsequent wheat ( L.) crops. In a 6-year on-farm canola-wheat rotation study conducted near Davenport, WA, grain yields of spring wheat (SW) following winter canola (WC) were reduced an average of 17% compared to SW yields following winter wheat (WW). Using soil samples collected and analyzed every year from that study, the objective of this research was to determine the differences and similarities in the soil microbial communities associated with WC and WW, and if those differences were associated with SW yield response. Microbial biomass and community composition were determined using phospholipid fatty acid analysis (PLFA). The WC-associated microbial community contained significantly less fungi, mycorrhizae, and total microbial biomass than WW. Additionally, reduced fungal and mycorrhizal abundance in SW following WC suggests that the canola rotation effect can persist. A biocidal secondary metabolite of canola, isothiocyanate, may be a potential mechanism mediating the decline in soil microbial biomass. These results demonstrate the relationship between soil microbial community composition and crop productivity. Our data suggest that WC can have significant effects on soil microbial communities that ultimately drive microbially mediated soil processes.
随着美国太平洋西北地区内陆油菜种植面积的增加，我们研究了这种相对较新的轮作作物对土壤微生物群落以及后续小麦作物表现的影响。在华盛顿州达文波特附近进行的一项为期6年的农场油菜-小麦轮作研究中，冬油菜（WC）后春小麦（SW）的谷物产量与冬小麦（WW）后春小麦的产量相比平均降低了17%。利用该研究每年采集和分析的土壤样本，本研究的目的是确定与WC和WW相关的土壤微生物群落的差异和相似性，以及这些差异是否与SW产量响应相关。使用磷脂脂肪酸分析（PLFA）来确定微生物生物量和群落组成。与WC相关的微生物群落中的真菌、菌根和总微生物生物量明显少于WW。此外，WC后SW中真菌和菌根丰度的降低表明油菜轮作效应可能会持续存在。油菜的一种杀生物次生代谢产物异硫氰酸盐可能是介导土壤微生物生物量下降的潜在机制。这些结果证明了土壤微生物群落组成与作物生产力之间的关系。我们的数据表明，WC对土壤微生物群落有显著影响，最终驱动微生物介导的土壤过程。
